Modern electrolytic copper refining

LIBRARY

OF THE

UNIVERSITY OF CALIFORNIA.
Clots

MODERN

ELECTROLYTIC COPPER
REFINING.

BY

TITUS ULKE, E.M.,
Consulting Eledro-Cbemist, * Member A E-C.S. and A.IM.E.

FIRST EDTTION.
FIRST THOUSAND.

UN!/,. ,: 3 IT Y

OF

NEW YORK :

JOHN WILEY & SONS.

LONDON: CHAPMAN & HALL, LIMITED.

1903.

GENERM

1903,

BY

TITUS ULKE.
(Entered at Stationers^ Halt)

ROBERT DRUMMOND, PRINTER, NEW YORK,

INTRODUCTION AND ACKNOWLEDGMENT.

THE great difficulties encountered in preparing the
following monograph can be fully appreciated only by
those who have undertaken a similar publication, and
might have prevented the consummation of this work,
undertaken at the request of several distinguished foreign
engineers, had I not been assured of the cooperation of
these gentlemen and of some of the leading electro-
chemists and refiners in the United States.

It is a well-known fact that the managers of but few
electrolytic plants grant technical visitors, and especially
writers, access to their works, and that it has hitherto been
extremely difficult or impossible, therefore, to secure accu-
rate descriptions of certain American and European refin-
ing appliances, methods, and works. Fortunately, I have
had the opportunity of personally inspecting many of the
most important electrolytic refineries in the world, in
several of which I have worked, and am therefore enabled
to present certain desirable information accurately for the
first time in print, and to supply close estimates of other
much-sought-for data.

Requests for information were addressed directly or in-
directly to practically every electrorefiner here and abroad,
with the object of making the following monograph as far
as possible an authoritative accurate, comprehensive and

iii

1 17590

iv INTRODUCTION AND ACKNOWLEDGMENT.

thoroughly up-to-date handbook. Its scope is indicated by
the numerous items of the table of contents.

Every electrolytic copper-refining plant in the world
that is now in commercial operation, I believe, is herein
tabulated with its actual or estimated output, arrangement
•of electrodes, location, etc., and is described as fully as a
personal inspection and inquiry, examinations of American,
British, German and French patents and literature, or
special means of securing information at my command,
permitted. The data thus gathered at the expense of con-
siderable work will, I trust, be appreciated by copper re-
finers especially, and aid in stimulating progress not only
in their rapidly extending art, but in electrometallurgy gen-
erally.

I take pleasure in acknowledging my indebtedness to
Mr. Lawrence Addicks, Raritan Copper Works, Perth
Amboy, N. J. ; Mr. Ottokar Hofmann, Director of the South-
west Chemical Co., Argentine, Kan.; and Mr. R. L. White-
head, Manager of the Seattle Smelting and Refining Co.,
Seattle, Washington, for permitting my use of their ex-
cellent articles in The Mineral Industry, vols. ix and x;
and to Dr. Jos. Struthers and the other editors and pub-
lishers of the Engineering and Mining Journal and Min-
eral Industry for a similar kindness extended by them ; Mr.
Wm. Thum, Ass't Sup't of the Balbach Electrolytic Copper
Works, Newark, N. J. ; and Mr. J. B. C. Kershaw, Electro-
chemist, London, for their valued cooperation; Prof. W.
Borchers, Aachen, Germany, for placing technical data
in his " Elektro-Metallurgie " at my disposal; Mr. Victor
Engelhardt, Chief Engineer, Siemens and Halske Co.,
Vienna, who assisted in obtaining information regarding
European plants and furnished descriptions of the Austro-
Hungarian refineries; Dr. Gustav Koelle, Director of the
Von Siemens Copper Works, Kedabeg, Russia, whose in-
teresting description of the Kalakent Works is given in

INTRODUCTION AND ACKNOWLEDGMENT. V

Chapter II, and to the following electrochemists, metal-
lurgists or engineers for rendering valuable assistance, or
managers of refineries for allowing me access to their
plants :

Mr. A. L. Walker, Manager, Perth Amboy plant of the
American Smelting and Refining Co.; Mr. Ed. Balbach,
Jr., President, Balbach Smelting and Refining Co.; Mr.
M. B. Patch, Superintendent, Buffalo Copper Works;
Mr. J. C. McCoy, Manager, Raritan Copper Works; Mr. W.
A. McCoy, Superintendent, Raritan Electrolytic Works;
Dr. James Douglas, President, Copper Queen Cons. Mining
Co. ; Dr. Edward Keller, Anaconda Mining Co. ; Mr. J.
T. Morrow, Superintendent, Boston and Montana Cons.
Copper and Silver Mining Co.; and the superintendents
of the Anaconda, Baltimore, Blue Island, and Nichols
refineries in this country, and of the Mansfeld, Oker,
and Altenau refineries abroad, as well as the following
engineers: Mr. J. R. Watson, Lake Superior Power Co.;
Mr. J. H. Hoff, American Bridge Co.; Mr. Willard Pope,
Canadian Bridge Co. ; Mr. A. L. Roby, Wellman-Seaver
Engineering Co., and Mr. G. J. Rockwell, of the Allis-Chal-
mers Co.

TITUS ULKE.

NEW YORK, March, 1903.

CONTENTS.

CHAPTER I.

PAGF

DEVELOPMENT, METHODS, AND APPARATUS OF ELECTROLYTIC

COPPER REFINING 1-55

Historical Data, i . Cost of Producing Electrolytic Copper,
3. Definitions and General Principles, 3. Comparison of
Methods, 7. Efficiency of Plants, 14. Stock of Metal in
Refining, 14. Sampling and Assaying, 16. Chemistry and
Physics of Refining, 17. Treatment of Solutions and Making
Bluestone, 27. Treatment of Slimes, 47. Resume of Modern
Practice, 51. Tables giving Outputs and other Data of Elec-
trolytic Copper Refineries, 52.

CHAPTER II.

DESCRIPTIONS AND VIEWS OF ELECTROLYTIC COPPER-REFINING

WORKS 56-147

(A) United States: i. Raritan Copper Works, 56. 2. Gug-
genheim Refinery (Perth Amboy Plant), 80. '3. Anaconda
Electrolytic Copper Refinery, 89. 4. Nichols Refinery, 99.
5. Baltimore Copper Works, 100. 6. Great Falls Refinery, 103.
7. Balbach Refinery, 107. 8. De Lamar Refining Works, no.
9. Buffalo Refinery, in. 10. Blue Island Refinery, 113.

(B) Great Britain: i. Bolton's Froghall Refining Works,
113. 2. Pembrey Copper Works, 115. 3. Bolton's Widnes
Refinery, 115. 4. Leeds Copper Works. 116. 5. Vivian Re-
finery, 123. 6. McKechnie's Refinery, 124.

(C) Germany: i. Hamburg Refinery, 124. 2. Mansfeld
Copper Works, 125. 3. Oker Refinery, 126. 4. Goslar Refinery,

vii

viii CONTENTS.

128. 5. Schladern Electrolytic Works, 130. 6. Niedermarsberg
Refinery, 131. 7. Altenau Electrolytic Works, 132. 8. Burbach
Refinery, 132. 9. Papenburg Electrolytic Works, 132.

(D) Austria-Hungary: i. Witkowitz Refinery, 133. 2.
Brixlegg Refinery, 135.

(E) France: i. Dives Electrolytic Works, 135. 2. Biache
Refinery, 136. 3. Pont de Cheruy Refinery, 136. 4. Marseilles
Electrolytic Works, 137.

(F) Russia: i. Kalakent Copper Works, 137. 2. Nikola jev
Refinery, 147.

CHAPTER III.

COST ESTIMATES OF AN AMERICAN ELECTROLYTIC COPPER AND
NICKEL REFINERY, WITH GENERAL PLAN AND DETAIL DRAW-
INGS 148-160

Description and Specifications, 148. Estimate of Costs of
Plant, Stock, and Operating, 150. General Expenditures, 151.
Cost of Office Building, 151. Cost of Power-house, 151. Cost
of Tank-house, 152. Cost of Furnace Building, 152. Cost of
Separating-house and Nickel Refinery, 154. Cost of Crystal-
lizing-house, 158. Cost of Silver Refinery, 158. Operating
Costs and Profit, 159.

APPENDIX.

CHRONOLOGICAL LIST OF PATENTS, BOOKS, AND SPECIAL ARTICLES
ON ELECTROLYTIC COPPER-REFINING METHODS AND APPA-
RATUS 161-165,

MODERN ELECTROLYTIC COPPER REFINING.

CHAPTER I.

DEVELOPMENT, METHODS, AND APPARATUS OF ELEC-
TROLYTIC COPPER REFINING.

Historical Data. — The art of electrolytically refining
crude copper is based, like the allied art of copper plating,
upon various discoveries chiefly made between the years
1800 and 1867, the date of the introduction of the dynamo.

Although more than thirteen hundred years ago Zosimus
mentioned the earliest known fact respecting the electro
lytic separation of metals, viz., that by immersing a piece
of iron in a cuprous solution it acquired a coating of copper,
it was first definitely shown in 1800 that copper could be
deposited from solution by electric currents, which fact
was demonstrated by Cruikshank.

After the discoveries of magneto-electricity by Faraday
in 1831 and of electrotyping in 1838 by Jacobi, the greater
possibilities of the application of electricity to metal
deposition began to be recognized, but not until Elking-
ton's discovery of the art of refining copper in 1865 and
the introduction of the dynamo in 1867 was its com-
mercial future assured. Since that time the remarkable
growth of electric copper refining is scarcely paralleled in
the history of any other industry.

3 MODERN ELECTROLYTIC COPPER REFINING.

It was nearly thirty-eight years ago that James Elkington,
the English silver-plater, invented the commercial electro-
lytic method of refining crude copper, and in 1869 that he
founded the first custom plant using this process, at Pem-
brey, Wales. The works established by the father of
modern copper refining are to-day in successful operation,
due chiefly to the remarkable fact that both Elkington 's
process and apparatus were well conceived and needed but
little improvement to bring them up to present standards.
However, it was not until the last two decades, when the
spread of electric lighting led to an enormous demand for
pure copper, and the perfection of the dynamo made pos-
sible the cheap generation of current, that the great im-
portance of Elkington 's invention was fully realized.

In Germany, according to Schnabel, the first electro-
lytic refining plant erected was the Hamburg refinery
(Norddeutsche Affinerie), built in .the late seventies un-
der Wohlwill's management and operated with Gramme
machines. Subsequently the Oker refinery (Communion
Huettenwerk) , in which Siemens machines were used to
generate current, was erected under Braeuning's manage-
ment, and in still more recent years, according to Schnabel,
the Mansfeld Copper Co.'s electrolytic plant was started.

In 1879 an experimental plant for refining copper by
electrolysis was operated at Phcenixville, Pa., but the first
commercial refinery in the United States was built by
Edward Balbach, assisted by F. A. Thum, at Newark, N. J.,
in 1882-83. The refineries at Baltimore, Md., and at
Anaconda and Great Falls, Mont., were not started until
1887, 1891, and 1892, respectively, the Raritan Copper
Works in 1899, and the De Lamar Works and the new Perth
Amboy electrolytic plant in 1902. Sixteen years ago the
Balbach and the Bridgeport (Conn.) works were the only
large electrolytic plants in America, and their total output
was less than 24 tons per diem. Yet to-day there are in

DEVELOPMENT, METHODS, AND APPARATUS. 3

operation ten electrolytic refineries, producing the enor-
mous quantity of 764 tons daily, or nearly two hundred
and seventy-nine thousand short tons of copper annually,
besides over twenty-seven million ounces of silver and three
hundred and forty-six thousand ounces of gold. Thus
over 80% of all the copper produced in the United States
is now refined in the electrolytic bath, and probably nearly
70% of the entire production of the world is now turned
out as electrolytic metal.

Cost of Producing Electrolytic Copper. — Still more aston-
ishing than the above figures of output is a comparison of
the cost of producing electrolytic from crude copper ten
years ago with the cost to-day. Then it was about $20
per ton, although refiners charged $40 and allowed only
92 \% on the commercial value of the silver in the Bessemer
or blister copper. Now the cost of refining 98% copper
anodes at several of the large works in the United States
has actually been lowered to $4 or $5 per ton, it appears,
and occasionally contracts for refining from anode to
cathode have been closed, I believe, for as low as $7.50.
The chief cause of the great reduction in the cost of refining
is economy in utilizing power and in handling material.

Definitions and General Principles. — The following defi-
nitions from Edward Keller's excellent article in Mineral
Industry, vol. vii, are reproduced chiefly in order to give
students a clear conception of the elementary principles
that underlie the practical working of the electrolytic
refining process, and thus make the subsequent treatment
of the subject more comprehensive :

"Wherever there is any work done by means of electricity
there are three governing factors, i.e., the electromotive
force, the resistance, and the electrical current. The elec-
tromotive force is measured in volts, and is technically
spoken of as voltage. The resistance is measured in ohms;
the current in amperes, and it is spoken of as having a

4 MODERN ELECTROLYTIC COPPER REFINING.

certain amperage. The relations that exist between these
factors are expressed in Ohm's law, upon which and the
simple deductions therefrom are based nearly all calcula-
tions in electrolytic work.

"Ohm's law, briefly stated, is this: "The resulting elec-
trical current is equal to the electromotive force divided
by the resistance." In other words, the electromotive
force (electrical pressure created by the dynamo) causes
the flow of the electrical current. The latter is directly
proportional to the former. The resistance opposes the
flow of the current. The latter is, therefore, inversely pro-
portional to the former. The electrical power is the product
of the number of volts multiplied by the number of amperes
of the current. Its unit is called a watt.

"From Ohm's law it follows that to double the resistance
halves the current, the electromotive force remaining con-
stant. Or if with the doubled resistance the current is to
remain constant, the electromotive force, and therewith
the power, must be doubled. This applied to electrolysis
means that with the same current we can deposit an infinite
quantity of copper, but that the power necessary must
ever increase proportionally to the resistance.

"Another important deduction from Ohm's law is the
following: When through a given resistance the current is.
required to be doubled, the power must be increased four
times ; or in general, the resistance remaining constant the:
power increases proportionally to the square of the current.
This applied to a practical example means that if from a
given number of depositing tanks we wish to double the
output of copper by doubling the current, we must increase
our power four times ; or should we wish to quadruple the
output the power must be increased sixteen times. We
therefore encounter the economic problem: Is it more
advantageous to double, quadruple, etc., the capacity of
an electrolytic plant as to number of tanks or to increase

DEVELOPMENT, METHODS, AMD APPARATUS. 5

four times, sixteen times, etc., the power in order to in-
crease the output proportionally to the former? The first
is a single investment, the second a permanent expense.

"The most important laws in direct relation to electrolysis
are those of Faraday, who showed that a given quantity
of current will always deposit the same quantity of a given
element, and that the elements are deposited, or their
compounds decomposed, proportionally to their equiva-
lent weights, e.g., hydrogen i, oxygen 8, copper 31.7, sil-
ver 1 08, etc.

"It has been demonstrated by careful experiment that
one ampere of current will deposit 1.18656 g. of copper in
one hour, which can be translated for technical purposes
to mean that one ampere of current should deposit i oz.
of copper in 24 hours. It is, therefore, an easy matter to
keep a record of the efficiency of a plant, or to detect leak-
ages of the current, by measuring the current, weighing
the deposited copper, and comparing the latter with the
theoretical quantity required. The quantity of current,
i.e. the number of amperes, flowing through a certain unit-
surface is termed the density or intensity of the current.
The greater the density of the current the greater will be
the rate of deposition of the metal on a given surface. In
order to deposit pure copper it is essential to have a con-
stant current density. The copper is, however, deposited in
satisfactory condition only when the current density is main-
tained within certain limits. The usual density employed
in the United States is 10 or 12 amperes per square foot.*

"Joule found that an electrical current passing through
a conductor generates a certain quantity of heat, and he
established what is known as Joule's law, namely, the
quantity of heat developed in a conductor is proportional
to the resistance of that conductor and to the square of
the current density. When heat is thus produced in the
conductors and the electrolyte it is a waste of power.

* Now 12 to 15 amperes. — Note by Author.

6 MODERN ELECTROLYTIC COPPER REFINING.

" The copper plate in the depositing tank which receives
the current, and is dissolved by the latter 's action, is called
the anode plate. The plate on which the deposition of the
metal takes place is called the cathode plate, and the two
are the electrodes. The solution in which they are im-
mersed is the electrolyte.

" In an electrolytic copper refinery the current must be
adapted to the given condition of electrodes and tank
arrangement, or the latter to a given current. For exam-
ple, if with a given current, say 1000 amperes, we wish a
current density of 10 amperes per square foot of anode sur-
face, and our anode plates have a surface of 10 sq. ft., it
is necessary to let the current pass through 10 such plates
connected in multiple. These would be placed in one tank
with, say, n cathode plates, through which the current
would pass into another tank of the same description, and
so on. Tanks are thus connected in series. As their num-
ber increases, the voltage necessary to carry the current
through them must increase proportionally. With the
increase of voltage the danger of loss of current through
leakage increases. There must, therefore, be a limit to
the number of tanks connected in series. The highest
voltage in present practice is about 180.

" The lower limit of a series is, of course, a single couple,
one anode, and one cathode, with an electrical pressure of
a fraction of one volt, the exact value depending on the
distance between the electrodes, the density of the current,,
the character of the electrolyte, and the composition of the
anode. In actual practice the voltage between plates,
varies between about \ and J- volt, according to the system
employed. The voltage necessary to decompose copper
sulphate and to deposit the metal on the cathode is theo-
retically 1. 1 6 volt. With a soluble anode this is counter-
balanced by the energy evolved in the formation of copper
sulphate on the anode surface."

DEVELOPMENT, METHODS, AND APPARATUS.

Comparison of Methods. — There are only two systems
of electrolytic copper refining proper now in use, which
differ chiefly in the mode of arranging the electrodes. They

FIG. 1

FIG. 2

FIG. 3

MULTIPLE

FIG. 4

s

RANDOLPH

FIG. 5

STALMANN

ANODE
CATHODE

SCREEN

Arrangement of Electrodes in the Different Systems of Refining.
FIG. 6 FIG. 7

FIG. 8

Various Arrangements of Conductors in the Multiple System.

(The dotted lines indicate the outlines of the tanks.)

are known as the multiple and the series processes, the
latter being employed in only two or three works, and the
use of the Smith, Stalmann, and Randolph arrangements
of electrodes having been discontinued. The scheme of

8 MODERN ELECTROLYTIC COPPER REFINING.

arrangement of electrodes and conductors in these various
systems is indicated in the subjoined cuts, Figs, i to 8, in-
clusive, from which it will readily be gathered that vertical
electrodes are employed in the Multiple, Hayden, and Stal-
mann processes, and horizontal electrodes in the Randolph
and Smith systems, and that the latter is the only one in
which screens to prevent the anode slimes from falling on
the depositing copper are interposed between the plates.
A few other processes, such as the Elmore, Emerson, and
Cowper-Coles methods for producing tubes and other
shapes, and Thofehrn's direct method of producing wire
bars, are more properly shape -producing than true refining
processes, and will therefore not be treated in this mono-
graph, excepting in so far as they have attained practical
prominence in copper refining. Neither will I discuss the
Marchese, Hoepfner, Siemens and Halske, and Keith
processes, as they apply particularly to ores and matte and
not to crude copper, and have not, it appears, proven
profitable.

Those who have to select a refining process and have
to operate electrolytic works, must consider the following
facts in comparing the two systems of refining:

The series or Hayden system, as developed in the United
States, differs from the commonly employed multiple
system in the following respects:

1. Special cathodes, as in the multiple system, are not
necessary, one side of the anode plate serving as cathode.

2. The anodes, excepting the first and last, are not con-
nected to copper conductors, the solution alone serving to
conduct the current, and the plates are placed in series.

3. Much larger tanks than those used in the multiple
system are employed, the size at the Nichols Works,
Brooklyn, being 16 ft. long, 5 ft. deep, and 5^ ft. wide.

4. The anodes used are either } or f in. thick and are
longer, thinner, and narrower than multiple anodes. They

DEVELOPMENT, METHODS, AND APPARATUS. , 9

are straightened by rolling at the Baltimore Hayden plant
and hammered straight by hand at the refinery of the
Nichols Company. At the latter works six anodes, each
4.5 ft. long, 10 in. wide, and weighing 65 Ibs., are suspended
abreast in a tank and form a row, while at the Baltimore
Copper Works a row is made tip of two anodes, a lower and
an upper plate, held at each side in a grooved slide. The
rows of anodes are placed 0.5 in. apart at Baltimore and
0.8 to 0.9 in. apart at the Nichols plant, and the drop in
potential between any two rows is therefore as low as
one-ninth of a volt.

The series system is used only by the Baltimore Electric
Refining Company and the Nichols Chemical Company, a
serious drawback being found in the large quantity of scrap
copper produced with this process, which averages about
twice as much as in the multiple process.

With the same solution, it is obvious that the voltage
required per tank will depend upon the area of the plates,
the distance of the plates apart, and the number of plates
in series. In a series tanjc, therefore, the electromotive
force must be many times greater than the electromotive
force required in a multiple tank; and where many plates
are arranged in series, the voltage required to maintain a
given density of current is very great and leads to short-
circuiting and other evil consequences, unless great care
is constantly exercised.

As Barnett states in Peters' "Modern Copper Smelt-
ing," one must also take into account that the slimes, as
they collect on the bottom of the tank, form a large con-
ducting plate. If the electromotive force is sufficient to
overcome the resistance between the bottom of the elec-
trodes and the layer of slimes, the current will flow partly
through the electrodes and partly through the slimes, in
amounts inversely as the resistance of the . two routes.
Owing to the lessened density of current at the electrodes

10 MODERN ELECTROLYTIC COPPER REFINING.

this will be manifest in a diminished output per tank.
That such short-circuiting occurs is proved by the fact that
more copper is deposited on the end electrodes in the series
than on the intermediate plates, for there the currents will
recombine to a greater density per square foot of deposit-
ing surface than elsewhere in the tank. Likewise the
observed rapid concentration of copper in the electrolyte
of series processes is probably largely due to the combined
chemical and electrolytic solution of the anode scrap in
the slimes.

Series tanks are constructed of slate, or of wood, lined
with some acid-proof non-conductor, as a lead lining mani-
festly could not be employed in the series system. Slate
tanks, although durable, are very expensive, as the average
cost of slate for electrolytic vats in the United States is
about 40 cents per square foot of i J in. thickness in lengths
not over 5 ft. ; but the cost advances at the rate of 5 cents
per square foot for every additional foot in length.

Wooden tanks, although cheap (they usually cost about.
$30 each), soon become efficient conductors and lose con-
siderable current by short circuits around the sides of the
tanks and leakage to the ground. This is partly because
the penetration of the acid sulphate of copper cannot well'
be prevented in tanks constructed of wood, even if lined
with tarred felt and asphalted. The older the tanks the
more subject are they to these disorders. That is one of
the reasons why, in the series system, only about 90% of
the theoretical deposit is obtained from a given current,
even with comparatively new wooden tanks, and that the
average efficiency falls far below this figure.

In two given plants having equal cathode surfaces
and using equal current densities the multiple system
requires only about one-half the anode copper used in the
series system. As refineries tie up between several hundred
and several thousand tons of copper each, the factor of

DEVELOPMENT, METHODS, AND APPARATUS. II

interest on one-half of this is not to be disregarded. In
series processes, therefore, the anodes are made thin, so
as to obtain the maximum depositing surf ace with minimum,
weight of anodes. But the greater care which must be
exercised in preparing thinner anodes, and the need of
more frequently renewing such anodes than the thicker
anodes used in the multiple system, entail fixed charges
which about balance the saving in interest effected by
using the thinner electrodes.

Maurice Barnett ably reviews the question of the
relative expense of operating the two systems of refining
in Peters' "Modern Copper Smelting," and reaches the
following conclusion:

* ' In order to compensate for the extra copper used in
the series system, it is the rule to economize in tanks and
solution by arranging the electrodes closer together than
is done in the multiple system. With electrodes close
together there is the possibility of sprouting and short-
circuiting, unless the current is maintained of uniform
density over the entire surface of the electrodes. Hence
arises the necessity, in series processes, of working the
anode copper up to a point where it is uniform and follow-
ing this by poling.-

"In the multiple system the copper does not neces-
sarily have to be improved and poled, although this pro-
cedure is not uncommon. At the Boston and Montana
Company's Works at Great Falls, Mont., the anodes are
cast direct from the converters, thus saving the entire cost
of remelting and refining the anode copper inherent in the
series system. To neutralize the inevitable consequence
of unequal corrosion following from such a procedure, it
1 is customary to place the electrodes from two to two and
one -half inches apart. There is not then the necessity for
maintaining a uniform density of current over the entire
surface, this inequality of density in the rougher plates

12 MODERN ELECTROLYTIC COPPER REFINING.

being overcome by changing the cathodes rather more
frequently than the anodes. Short-circuiting from sprout-
ing is thus prevented and the inequality of density of cur-
rent neutralized. In the series system, 'stripping' the
deposit cannot be economically practiced until the tank,
as a whole, is ready to be emptied.

' ' Of course the use of less pure copper in the anodes
in the multiple system tends to make the electrolyte impure
and increase the cost of refining by necessitating renewals
of the electrolyte. This is true, however, only where no
effort is made to keep the electrolyte free from the im-
purities that enter it from the anodes. At first sight it
would appear as if the extra expense in preparing the
anodes would be justified, because smoother and thinner
electrodes can be brought closer together — say to one-
half the usual distance allowed in the multiple system,
resulting in a reduction of the resistance between electrodes
and a doubling of the output per horse-power of mechanical
energy expended.

"While the output is undoubtedly increased in this
way, it cannot at best be more than double the output
under the multiple system save where the anodes are rolled
plates. Here the resistance between electrodes is as low
as one-third that between electrodes in a multiple tank.
The expense, however, of rolling the plates and the greater
cost of stripping indicate that economv cannot be effected
along these lines.

* ' In a general way it may be stated that the cost of
improving and poling anode material exceeds the saving
resulting from increased output per horse -power of mechan-
ical energy expended. The multiple system, moreover, is
free from the costly process of stripping the deposited cop-
per from the anode scrap. This separation is frequently
so difficult a matter that the deposited plate is often thrown
back into the blister furnace along with the rest of the scrap.

DEVELOPMENT, METHODS, AND APPARATUS. 13

"Furthermore, the cost of maintenance of plant is
greater in the series process, owing to the fact that the life
of the tanks, when made of wood, is limited to about four
years. Series arrangements gain slightly from the circum-
stance that there is less loss of energy in the conductors
than in the multiple system, where there is always a con-
sumption of about 5% to 8% of the mechanical energy
of the circuit. Where coal is cheap, this is not very im-
portant. The interest charges on the plant are also slightly
in favor of the series system. This favorable factor of the
latter is offset by heavier cost of renewals and larger interest
on stock. The series system is free from the expense of
making cathodes, inherent in the multiple system, but is
still subject to heavy charges for stripping, amounting to
four times that of making cathodes.

' ' Balancing these various factors as well as is possible
in two works operating under the same conditions of cost
of labor and fuel, there is a saving in the operating ex-
penses, in using the multiple system, of nearly $2 per ton
of refined copper. This difference is susceptible of greater
increase if the refinery is run as part of a converting estab-
lishment; for since anodes may be made direct from the
converters, the expense of making them in the reverber-
atory, amounting to from $2 to $3.40 per ton, is altogether
avoided.

"In general, the greater first cost of works using the
multiple system lies in the extra expense of the tank con-
ductors and plates for making cathodes plus about one-
half of the value of the lead lining of multiple tanks plus
one-third of the value of the steam and power plants. How-
ever, in spite of its larger first cost, the multiple system is,
undoubtedly, susceptible of greater economy than is pos-
sible under series arrangements, as is shown by its adop-
tion, after costly and exhaustive experiments, in works
where the series system was formerly used.

14 MODERN ELECTROLYTIC COPPER REFINING.

"To sum up the preceding points, the current effi-
ciency of the multiple process averages 95% as against
90% for the series process under similar conditions; much
less copper is held back in the multiple than in the series
system, and the relative cost of operating it is probably
.less by nearly $2 per ton. ' '

Efficiency of Refining Plants. — Attention should be
^called to an important point sometimes overlooked by
refiners, namely, their frequent waste of power, or the low
^energy efficiency of certain copper works. While the cur-
rent efficiency of these same works, or quotient of the
amperage employed for a given output divided by the
theoretical amperage required to deposit the same amount
of copper, may be as high as 90% or 95%, their energy
efficiency, or quotient obtained by dividing the energy or
current consumed in doing useful work by the total energy
furnished by the dynamo, is sometimes only 30%, and in
the average refinery it does not often exceed 65%.

The loss of energy is due partly to bad metal contacts
and short-circuiting and partly to the use of voltages much
in excess of those actually required to overcome the resist-
ance of the solution and of the metal conductors. These
facts show how important it is in electrolytic refining to
exercise close supervision, and how its absence is often
paid for in heavy waste of energy or by its equivalent
value in coal or money.

Stock of Metal in Refining. — It is interesting to note
the great reduction in recent years of the stock of metal
required in copper refineries per unit of output.

Recognizing the disadvantageous features of the elec-
trolytic process of refining copper to be, i, the large cost
of plant; 2, the constant attention required to be paid
to the process; 3, the comparatively large amount of
covered space necessary; and 4, the continuous period
of time during which a considerable stock of metal remains

DEVELOPMENT, METHODS, AND APPARATUS. 15

unproductive of interest, refiners turned their attention
chiefly toward the last as offering the greatest field for
improvement. Their efforts in this direction have been
eminently successful, especially in the United States.

Fifteen years ago it was not at all uncommon for copper
refineries here and abroad to require 75 to 100 times as
much copper as was daily produced in their electrolytic
plants to stock their tanks for regular work. Subsequently
improvements of various kinds brought this amount down
to 50 or 60 tons for every ton of copper produced; yet
to-day, in several cases, only 15 to 20 tons are required
per i ton of output.

This great improvement, which has so largely reduced
the cost of copper refining, is due chiefly to the employ-
ment of an increased density of current, resulting in more
rapid working and a greater output with the same stock
of copper and solution. Formerly current densities of 2
to 4 amperes per square foot of cathode surface were com-
monly used in refining; yet to-day they average from 12 to
1 6 amperes in the United States, and in one or two works
current densities of as much as 35 or 40 amperes are em-
ployed. The quantity of copper undergoing treatment
with the same output of metal is thus correspondingly
reduced to one-fourth, and in some cases less than one-fifth,
of what it was formerly. One must not overlook the fact,
however, that there are important limiting factors to this
tendency to increase the current strength and thereby
reduce the stock required. In the first place, the maxi-
mum allowable flow of current and the minimum permissi-
ble rate of circulation and speed of purification depends on
the richness of the anode in precious metals and on its
contents and that of the solution in arsenic and other im-
purities. If large quantities of these are present, a high-
current density, which is of course accompanied by a high
rate of anode dissolution and an impure electrolyte, would

1 6 MODERN ELECTROLYTIC COPPER REFINING.

carry part of the silver and arsenic to the depositing copper,
chemically or mechanically, and thus reduce its purity and
its electric conductivity, if special means or prevention are
not adopted. With very pure crude copper, on the other
hand, current densities as high as 30 and even 40 amperes
may be used.

In refining plants treating arseniferous copper bullion
rich in precious metals, the average electric current is not
over 8 to 10 amperes per square foot (counting both sides,
of the cathode plate), while those producing electrolytic
copper from a good or extra good quality of copper bullion
may employ three or four times this current density.

Under modern conditions, a 1 5-ton plant does not
usually require stocks of more than 200 to 300 tons of
copper to be placed in course of treatment, while 600 to 900
tons were formerly considered necessary for a daily output
of 15 tons. With plants of any given capacity much
smaller tonnages in stock are considered adequate nowa-
days than in former times.

Besides the total stock of copper in the tanks, however,
there is generally tied up from 50% to 100% of this quan-
tity in the form of blister copper for making anodes, main
conductors, new anodes ready for immersion, residues of
old anodes, solution and stock of refined copper.

It appears that the total amount of copper in process
of treatment — stock, solution, and conductors — averages 10
to 20% of the yearly output of our electrolytic copper works,
as against a permanent stock of 30% to 40% formerly.

Other things being equal, this means a great reduction
of the period of time during which the stock of metal re^
mains unproductive of interest, or an equivalent decrease
in the amount of working capital required for a given out-
put in refining copper.

Sampling and Assaying. — -With regard to the sampling
of- blister copper and anodes, E. Keller proposes the follow-

DEVELOPMENT, METHODS, AND APPARATUS. 17

ing improvement: It has been found that samples taken
from different portions of anode plates and pigs of blister
copper are apt to vary considerably in their percentages
of gold and silver, as well as base metals, owing to their
segregation in cooling, and that the common method of
securing samples by drilling, punching, or chipping often
leads to erroneous results. A more rational and satisfac-
tory mode of sampling is to take the sample when the
copper is in the furnace and after the charge has become
thoroughly mixed, and either to pour a shot sample from
a ladle in which the whole metal is liquid or to cast a
sample plate the thickness of which is small compared
to the other two dimensions, and to drill or punch a sample
from this plate.

With electrolytic copper, not only different plates from
the same tank, but different portions of the same plate may
show a different composition, and the sampling is only
satisfactory after the cathode plates are melted down and
the furnace charge has become thoroughly mixed.

Refiners have unfortunately not yet agreed upon stand-
ard methods of assaying and analyzing blister copper, fur-
nace slags, anodes, cathodes, slimes, and refinery solutions,
and to describe all the methods in use at the various plants
here would require more space than I have now at disposal.
The reader is therefore referred to descriptions and dis-
cussions of the various methods that have appeared in the
Engineering and Mining Journal, Dec. 16, 1899, and The
Mineral Industry, vol. ii, pp. 276-277; vol. viii, p. 187;
vol. ix, pp. 226-229, and vol. x, p. 228.

The Chemistry and Physics of Refining. — Prof. M. Kiliani,
in 1885, was the first investigator to call attention to many
of the following chemical and electrochemical reactions
involved in copper refining.

With a normal current density of 2 amperes per square
loot and an electrolyte containing 150 g. blue vitriol and

1 8 MODERN ELECTROLYTIC COPPER REFINING.

50 g. sulphuric acid per liter, the cuprous oxide contained
in the anode because of its poor conductivity remains
unattacked and accumulates in the anode residue or
slimes. By a secondary reaction, however, it gradually
dissolves and thus reduces the acidity of the solution and
increases the copper contents of the latter.

Silver, gold, and platinum, unless present in considerable
quantities, and unless the solution is not of normal strength,
are completely recovered in the tank residues, barring
0.2-0.3 oz. Ag per ton found in almost all cathode copper.
If the solution becomes neutral, silver is dissolved and apt
to be deposited on the cathode. The solution of the silver
is checked by the addition of salt or a small beakerful
(say 300 cc.) of hydrochloric acid to the contents of every
electrolytic tank.

It has not yet been definitely settled whether the arsenic
in the anode is present chiefly as metal or as arsenate of
copper. In the former case it passes into solution during
electrolysis as arsenious acid, and arsenic is not deposited
until the electrolyte has become saturated with this acid.
When arsenate of copper is found in the anode, this salt,
being a non-conductor of electricity, is not altered in its
composition, and forms part of the residue. In the course
of time, however, arsenious acid is dissolved as a secondary
result of the action of the free sulphuric acid of the elec-
trolyte, and a certain amount of green, insoluble, slimy
.arsenite of copper is eventually formed. This secondary
formation of arsenious acid can be diminished by frequently
removing the slime film from the anodes, i.e., lifting the
latter out of the tanks and washing off their adhering slimes
into a special receiver. From a neutral bath or a solution
containing an insufficiency of copper, arsenic is deposited
on the cathode with the copper. Some American refiners
add 0.5% and others up to 20% of ammonium sulphate to
the electrolyte to hinder as much as possible the electro-

DEVELOPMENT, METHODS, AND APPARATUS. 19

deposition of arsenic with the copper. The limit of arsenic
allowed in the cathode copper for making wire bars is
understood to be 0.002% at the Balbach Works and o.ooi %
at the Nichols Refinery.

Antimony, if found as metal in the anode, partly dis-
solves at first, although a portion of this dissolved antimony
may eventually precipitate as a neutral salt, and partly
forms an insoluble basic sulphate of antimony, which coats
the anode. In the course of time antimonious acid is
formed, on account of the secondary action of the free sul-
phuric acid present. Antimony is not electrolytically
deposited on the cathode as long as the solution is nearly
normal in composition (containing 5% to 6% free acid and
15% to 20% bluestone), even if the electrolyte is so sat-
urated with antimony that its basic salts begin to separate.
At the worst a little basic antimony compound may be
mechanically deposited on the cathode and form a black
coating containing both copper and antimony. Antimony
is apt to deposit with the copper and cause the latter to
become dull colored, brittle, and to form needle-like pro-
jections whenever the solution becomes neutral, but if
the solution contains an insufficiency of copper, antimony
is invariably thrown down on the copper, even when con-
siderable free acid is present.

Iron in the anode dissolves more readily than the copper
and forms ferrous sulphate, which in time is partly oxidized
to ferric compounds. These are produced freely and
directly whenever the density of the current reaches 1300
amperes per square meter. "Sprouting" of the cathode
is produced, if iron is allowed to replace copper in the elec-
trolyte, until there is but 2 g. of copper present to the liter
of solution.

Copper deposited with a weak current from a neutral
solution, even if the latter is free from impurities, is often
so brittle that it can be readily pulverized. This is due

20 MODERN ELECTROLYTIC COPPER REFINING.

to the fact that the copper contains cuprous oxide. Of
course the neutralization of the electrolyte also decreases
the conductivity of the solution, so that its resistance with
anodes 5 cm. apart, for example, may be raised from, say,
o.i volt (normal) to 0.25 volt. A weak current is not able
to completely decompose the copper sulphate into Cu and
SO4, so that some Cu2O is deposited with the copper. This
deposit of Cu2O decreases with increasing current strength
up to that point at which the current is strong enough to
throw down absolutely pure copper.

In acid solutions the cuprous oxide of the cathode is
decomposed by a secondary action, while in a neutral elec-
trolyte it remains on the cathode. Roessler's hypothesis
may explain why certain refiners associate a green solution
with bad cathode copper, good copper being deposited
from the same solution, as soon as it changes its color from
green to blue. Roessler believes that under certain con-
ditions metallic copper reduces an acid solution of cupric
sulphate and forms cuprous sulphate, which is subsequentlv
oxidized by the air to cupric sulphate. The quantity of
copper so dissolved increases with the rapidity of the cir-
culation, i.e., the more the electrolyte is exposed to the
atmosphere, and with the diminution of the density of the
current. The more thoroughly the circulation is kept up,
the purer, more finely crystalline, and more flexible will be
the deposited copper, even with nearly pure solutions and
under otherwise normal conditions.

Tellurium and selenium, which are frequently present
in anode copper, probably as telluride and selenide of silver
or copper, have but little effect, it seems, on the purity of
the copper deposited.

It is, of course, very important that the acidity of the
.electrolyte be determined daily and that the normal com-
position of the electrolyte be maintained.

.Since the time of the appearance of Kiliani's masterly

DEVELOPMENT, METHODS, AND APPARATUS. 21

essay, the accepted views of some of the reactions involved
in electrolytic refining have slightly changed. Credit is due
Dr. Emil Wohlwill for his recent work in connection with
observations of such reactions and their explanation, as
given in the late revised edition of Bore her 's "Elektro-
Metallurgie, " pp. 198-206. Wohlwill finds that Kiliani
underrated the importance of the presence of finely divided
metallic copper in the anode residue. Such copper, sepa-
rating out from anodes that are free or comparatively free
from impurities, appears of a dark reddish or rich red color
as long as discoloring impurities are absent. The amount
of such finely divided metallic copper (termed anode powder)
produced depends chiefly on the current density used, and
varies according to the following principles : i , the less the
current density the greater the quantity of powder forming in
a given time ; 2 , with the same current density the amount
produced increases with an increase in the acidity of the
electrolyte; and 3, under otherwise similar conditions, the
quantity of anode powder formed varies inversely as the
duration of uninterrupted electrolysis.

The following hypothesis may serve to explain the above
phenomena. During electrolysis a small amount of cuprous
sulphate forms at the anode along with the cupric sulphate,
only to decompose again in contact with the anode or in
its immediate vicinity into copper and cupric sulphate,
somewhat as copper, dissolved in a hot solution of cupric
sulphate, separates out as metal when the solution is
refrigerated. But as the current density decreases, the
number of univalent ions forming along with the bivalent
ions increases, and consequently the greater the amount
of anode powder produced.

In Wohlwill 's opinion, the separated copper powder in
contact with the unattacked copper of the anode acts like
an electro-negative or less soluble metal and consequently
protects the copper surface it covers. The electrolytic

22 MODERN ELECTROLYTIC COPPER REFINING.

action is thus restricted to the uncovered portions of the
anode and therefore to a decreasing area, which means that
the current density increases and thus diminishes the
number of univalent ions forming in a given time. This
hypothesis accounts for the fact that the excess of the loss
in weight of the anode over the increase in weight of the
cathode varies inversely as the time during which electroly-
sis is continued. Moreover, it explains why the anode
surface becomes rough or pitted, as chemical solution
alone without the formation of this protective metallic
powder would naturally tend to keep the anode surface
smooth. Smooth surfaces are only secured when cuprous
ions are produced in negligible quantities, as when high-
current densities are maintained. Additional proof of the
correctness of the above hypothesis lies in the absence of
any such anode powder in the electrolysis of chloride solu-
tions with copper anodes.

The separation of the red powder of metallic copper at
the anode in sulphate solutions furnishes a valuable means
of detecting the purity of the copper that is being dissolved;,
for even very small amounts of impurities produce a darken
ing in color of the separated anode powder and anode itself,
so that anodes of all sorts of copper not previously refined
electrolytically, or of copper deposited so carelessly as not
to avoid the codeposition of such impurities as arsenic or
antimony, invariably turn very dark. Hence one may
easily determine if the electrolytic process is being properly
carried on by periodically removing samples of the cathode
copper and suspending them as anodes. With the low-
current densities in vogue at the Hamburg Refinery the
anode residue naturally carries considerable finely divided
metallic copper. The latter product is probably the chief
cause of the gradual decrease of the acidity of the electro-
lyte and increase of its copper sulphate contents, as it readily
dissolves in dilute sulphuric acid in contact with air to

DEVELOPMENT, METHODS, AND APPARATUS. 23

copper sulphate. This increase of the bluestone contents
and decrease of acidity is therefore especially noticeable
in installations in which air is used to circulate the solution
and equalize its density, and is not, in WohlwilTs opinion,
due chiefly, as was formerly thought probable, to the
chemical action of the dilute sulphuric acid on the cathode
copper. At Hamburg fully 2% of the copper contents of
the anodes are recovered annually in the form of blue stone.

Another regular constituent of the anode slimes of
refineries is chlorine combined with copper. Whenever
the water used in electrolysis contains large quantities of
chlorides, the anodes are covered with a white coating of
cuprous chloride, which darkens in time through the action
of the air to dirty green-colored oxychloride. Eventually
this is further decomposed by the sulphuric acid of the
electrolyte and contributes also to the increase of the blue-
stone contents of the latter. Copper electro-deposited from
chloride solutions and salty river-water always contains
chlorine when low-current densities are employed. It may
then be noticed, when cathodes are arranged as end plates,
that the backs of the latter become covered with white or
green cuprous chloride. The latter sometimes adheres so
firmly as to occasion considerable trouble in the refinery
and necessitate the partial resolution of such plates, or the
substitution of an anode for the cathode at the ends of
such tanks, to distribute the current density uniformly
over the cathodes, and thus obtain good electrolytic copper
on all of them.

Wohlwill found that the copper deposited on lead strips,,
hung as cathodes alongside of the regular cathode sheets,
as a means of checking the changes in the electrolytic prod-
uct, when stripped off weekly was very brittle imme-
diately after starting a tank system with an electrolytic
solution containing salty water, and that the deposits made
later were less and less brittle. After running for a few

24 MODERN ELECTROLYTIC COPPER REFINING.

weeks the deposited copper was so tough that it could be
bent back and forth twenty' times without breaking. De-
terminations then made proved, according to Dr. Wohlwill,
that the brittleness of the cathodes varied directly as the
chlorine contents of the latter and of the solutions.

In my opinion this statement requires modification,
at least in so far as its bearing on American practice and
•conditions is concerned, for refiners in the United States
find, in starting deposition from a normal acidified copper
sulphate solution free from hydrochloric acid, that the
starting sheets are generally brittle, and that good tough
starting sheets may be secured by adding a small pitcher-
ful (about 300 cc.) of hydrochloric acid to each tank. Dr.
Wohlwill also came to the conclusion that it would not be
good practice to employ an electrolyte free from chlorides.
He encountered great difficulty for many years at the Ham-
burg Refinery, because periodically the deposited copper
became covered with octahedral crystal aggregates. Al-
though these crystal groups, often as much as 10 cm. long,
consisted of pure copper, practical considerations demanded
taking means for preventing their formation or their prompt
removal, naturally at the cost of much labor and expense,
and often of serious delay in the contract time of deliver-
ing cathodes. It was found that these troubles reached
their maximum when the water used as the basis of the
•electrolyte contained the least salt, say in January, and
were least when the solution contained the most salt, as in
July and August. The addition of sodium or magnesium
chloride in the first case immediately improved matters.
However, it did not entirely prevent the formation of needle-
like projections, so that a satisfactory explanation of the
above phenomenon is still wanted. The peculiar dis-
covery was made later that a solution of the above diffi-
culty lay simply in periodically interrupting the process
of electrolysis. By stopping the action of the current in

DEVELOPMENT, METHODS, AND APPARATUS. 25

all the tanks for, say, half an hour during each day, Wohl-
will found that the sprouting of the cathodes was dimin-
ished to such an extent as not to require any further
special attention, and has now adopted this practice in
the Hamburg Refinery.

As far back as 1886, Huebl determined experimentally
that the tensile strength and hardness of electrolytic copper
is not dependent on the concentration of the electrolytic
solution, but increased with increased current density, and
reached maximum values with an electrolyte containing
20% bluestone when the current density was 22 to 30
amperes per square foot. With the above composition
of solution the highest elastic limit was obtained when the
current density reached 10 to 15 amperes per square foot
and the greatest toughness at 6 amperes per square foot.

Foerster and Seidel finally investigated the influence of
temperature during the electrolysis of copper, and in 1889
published figures showing that they secured the toughest,
finest, and most evenly crystallized copper when they
heated the electrolyte to 40° C.

Woolsey McA. Johnson* assumes that ordinary copper
anodes may be considered as being mixtures of pure copper
and copper-silver alloys, cuprous oxide, and oxides of anti-
mony and arsenic, or solutions of these alloys and oxides
in pure copper, and states that, in his opinion, because
the electrical resistance of copper-silver alloys and of the
oxides is higher than that of pure copper, the silver alloy
and oxides would tend to ''slime" under normal condi-
tions and thus tend to keep the solution in a pure con-
dition. To explain these views, which have been more or
less well recognized since 1885, when Dr. Kiliani's pioneer
investigations were published, Johnson has recourse to the
following known facts:

* Paper read at the meeting of the American Electrochemical Society,
Sept. 1 6, 1902.

26 MODERN ELECTROLYTIC COPPER REFINING.

1. Every metal has a certain specific electrolytic ten-
sion or voltage depending upon its temperature, physical
condition, and the solution in which it dips.

2. Every metal has a specific electrical conductivity.

3. These two properties are profoundly modified by
alloying with other metals.

On these properties of the resulting alloys segregated
in the anode depends the selective electrochemical dis-
solution.

Metals unite with one another to form alloys, in most
cases with the evolution of heat, and the atoms are then
united with a firmer bond. In other words, the free energy
is diminished, and as the electrolytic solution tension is
measured by the free energy of the metal, in normal solu-
tion of its ions, it also must decrease. The resultant
product is harder and has less tendency to dissolve.

That most alloys of any two metals show a poorer con-
ductivity than the mean conductivity of the metals com-
posing such alloy, and in many cases than the conductivity
of either metal alone, is well known. These facts have an
important bearing, in electrolytic refining, in determining
the behavior of alloys and oxides contained in ordinary
copper anodes. For instance, if we consider a particle of
silver-copper surrounded by pure copper crystals, the
effect of the great difference in electrical conductivity is
pretty certain to shunt the current around this silver-
copper alloy and finally dissolve its copper backing. It
then can be brushed off into the slime. This, of course,
applies to all the alloys (and oxides) that have a low con-
ductivity.

Arsenic and antimony, were they present in the anode
as metals, would have a greater tendency to dissolve than
copper, because of their high electrolytic solution tension.
Fortunately for the electrolytic refiner, however, the larger
portion of these elements are thoroughly oxidized, either

DEVELOPMENT, METHODS, AND APPARATUS 27

in the converter or reverberatory furnace. The copper is
then brought to * ' set " in the refining furnace before cast-
ing into anodes if the copper is not cast into anodes direct
from the converter, receiver, or the mixer. The heats of
oxidation of arsenic or antimony being many times larger
than that of copper, the oxides of the former metals are not
reduced to any extent in the ''poling" operation in the
refining furnace as long as any cuprous oxide is left. Ar-
senic and antimony are thus present in oxidized anodes
mainly as insulators, and as such pass into the slimes
directly.

Treatment of Solutions and Making Bluestone. — The ten-
dency of the electrolyte with long use in circulation to
dissolve or carry in suspension impurities in dangerous
quantities, so that its continued use would cause disturb-
ance or the deposition of arsenic, antimony, bismuth, and
other metals or of their combinations on the cathodes,
i.e., the production of a copper unfit for electrical purposes,
must be opposed either by regularly purifying the solution
and continuing its use, or better, by withdrawing a portion
of the electrolyte from the regular circulation system
altogether, treating it separately and replacing the por-
tions so withdrawn by an equal quantity of fresh and pure
solution. In most works this purification or withdrawal
of the solution does not occur periodically, but is carried
out as one continuous operation, a certain portion of the
electrolyte always being under treatment. Moreover, as
the electrolyte also tends to become richer in copper sul-
phate than the standard fixed upon, this excess of copper
must likewise be removed, either by depositing out the
excess of metal in special tanks with lead anodes and very
strong currents or recovering the copper as bluestone by
crystallization. Both methods are commonly employed
in the same refinery.

After the recovery of copper vitriol from the discarded

28 MODERN ELECTROLYTIC COPPER REFINING.

electrolyte, by concentrating the solution up to 38° to
42° B. and crystallizing out the contained blue stone, the
crystals formed, if necessary, being purified by repeated
solution and crystallization until of marketable purity, the
impure mother liquors are treated for the recovery of the
remainder of the copper, usually by precipitation with
scrap iron, in which case the acid is usually wasted, or by
such means as secure the sulphuric acid in addition.

The sulphuric acid may be recovered by evaporating
down the foul solution until the basic salts of iron and
copper separate out and withdrawing the supernatant
sulphuric acid for use in treating silver slimes or in acid-
parting of dore bars.

It is, I think, a rather dangerous practice to allow the
impurities to accumulate, before regenerating the electro-
lyte, until the quality of the copper is jeopardized, as noted
in one plant. A regeneration method that has given com-
plete satisfaction is described in this monograph under
the caption of the Kalakent Works in Russia. It consists,
briefly, in neutralizing the sulphuric acid in the solution
by passing it over dead roasted matte and through roasted
copper ores, diluting and heating the solution to 50° C.,
and injecting compressed air through it, whereby the con-
tained impurities are precipitated, aided by suspending
anode scrap in the solution to completely neutralize the
same and form copper sulphate. After the separation of
the impurities the solution is concentrated and clarified
in special tanks, and being now pure enough, is acidified
and returned to the copper-depositing system for reuse
as normal electrolyte. The excess of purified electrolyte
which gradually accumulates with this regeneration method
is worked up into bluestone as usual.

Several similar methods of purifying the electrolyte
have been suggested, such as (i) filtration through a bed
of copper oxide, and (2) oxidation with jets of air.

DEVELOPMENT, METHODS, AND APPARATUS. 29

The method of purification believed to be in use at
Anaconda consists in repeatedly passing the impure elec-
trolyte through a filter of oxidized granulated copper, which
precipitates part of the impurities, and in oxidizing the
solution, now neutral and saturated with copper, by intro-
ducing jets of air. The oxidation is said to cause the
partial precipitation of the iron and other impurities in the
solution.

An analogous improvement in the mode of circulating
the solution was introduced into the old Guggenheim Re-
finery. This is based upon the well-known action of
Pohle's air-lift or of Siemens' ' ' geyser-pump. ' ' It consists
in blowing air under 3 or 4 pounds pressure into the elec-
trolyte by means of lead pipes in such a way that solution
is drawn from the bottom of the tank by a lower pipe and
delivered into an upper pipe, to be discharged back into
the tank through a large number of perforations in this
upper pipe. The electrolyte is thereby subjected to the
oxidizing influence of air-jets, whereby the precipitation
of some of the impurities suspended in the electrolyte is
facilitated and the latter is clarified. Many refiners believe
that a large portion of the arsenic, antimony, silver, etc.,
found in poor cathode copper is not deposited from the bath
electrolytically, but mechanically, by suspended impuri-
ties settling on the rough surface of the cathode. This is
especially the case when high densities or cloudy solutions
containing floating impurities are employed. The advan-
tage of a rapid clarification of the electrolyte is therefore
evident. At first the importance of the air circulation
and oxidation system was much exaggerated, especially
as regards the removal of the arsenic, and a claim was made
that it would altogether obviate the necessity of the usual
system of circulation and purification. Although such
general statements were not justified, the fact remains that
the air circulation, if assisted during two or three hours

3° MODERN ELECTROLYTIC COPPER REFINING.

in every twelve by the general circulation of the solution
from tank to tank, gave better results than when the old
system was used alone.

The recovery of the bluestone from the discarded
electrolyte is often accomplished as follows :

The solution is first boiled in lead-lined tanks with
granulated or scrap copper, steam and air being introduced
by means of a Koerting injector, so as to neutralize the
free acid and to increase the copper contents of the solu-
tion to the degree desired. It is then pumped up to the
crystallizing tanks, in which bluestone is secured by allow-
ing the copper sulphate to crystallize out, as the solution
cools, on bands of lead suspended in the saturated solution.
The mother liquor siphoned off contains most of the arsenic
and antimony originally present in the electrolyte, together
with some remaining copper. To recover the latter, the
mother liquor is usually treated in special tanks with sheets
of scrap iron. This metal first precipitates out the copper
and then the arsenic, so that a black precipitate is finally
secured, containing at times as much as 60% of metallic
arsenic. The impure precipitate, finally, is melted and
reduced down into arsenical copper bars, or occasionally
utilized in the manufacture of compounds of arsenic and
copper, such as Paris green.

At the Baltimore Copper Works the adopted method
of preserving the purity of the main electrolyte consists in
periodically withdrawing a fixed portion — say one-fifth—
of the electrolytic solution for manufacture into blue
vitriol and replacing it by fresh electrolyte, so as to keep
the percentage of impurities in the circulating electrolyte
down to an approximately constant figure. The composi-
tion of the solution, strength of current, and other factors
of refining not being permitted to vary within large limits,
it is comparatively easy to produce a nearly uniform quality
of copper. The bluestone recovered is sold at a fair profit,

DEVELOPMENT, METHODS, AND APPARATUS. 31

and the mother liquor from the blue vitriol works is finally
treated with scrap iron to precipitate the last 2% or 3%
of copper it contains.

A mode of treatment similar to the Baltimore process
is employed at the Balbach Refinery. Here the standard
composition of the electrolyte is kept up by periodically
running off a portion and replacing it with pure solution.
The impure liquid is then pumped to the vitriol works, in
which sulphates of copper, iron, and nickel are recovered
from the solution by a process of fractional crystallization,
.after which the mother liquor is boiled down to recover
arsenious and sulphuric acid. If the electrolyte contains
considerable antimony, part of it is said to precipitate as
gray metallic antimony or as antimonious acid in the dis-
charge launders.

From a consideration of all of the above-described
methods, we reach the conclusion that a crystallizing plant
for the recovery of blue vitriol, although bulky and cum-
bersome, is still considered a necessary adjunct to copper
refineries. However, by diminishing the need of blue
vitriol works of large capacity, and thus avoiding the
•excessive production of what is often a drug on the market,
the adoption of the best methods described above by refin-
ing companies has certainly resulted in keeping down the
cost of refining copper.

Ottokar Hofmann describes his important improve-
ments in the method and apparatus for purifying foul solu-
tions and making bluestone substantially as follows in The
Mineral Industry, vol. x. As applied to foul refinery solu-
tions, Hofmann' s process begins in elevating the latter by
means of a pressure tank, shown in Figs. 9, 10, and n,
to the purifying towers, the hard-lead pumps formerly
used for handling copper solution having proved failures.
On account of occasionally having to handle residues, the
pressure tanks are in an upright position and are constructed

32 MODERN ELECTROLYTIC COPPER REFINING.

as follows : * ' The body consists of two cylindrical sections
4 ft. long and 4 ft. 6 in. in diameter, the bottom being of a
spherical section of 2 ft. 3 in. radius and the top rounding
upward to a height of 6 in. above the rim. The sections

FIG. 9. — Plan showing Size of Openings.

FIG. 10. — Section on Line AB. FIG. n. — Plan of Supporting Frame.

FIGS. 9, 10, and n. — Cast-iron Pressure Tank.

are tightly flanged, with a rubber gasket between. Four
pipe connections are made through the top; the discharge
pipe entering through the center passes nearly to the bot-
tom and the filling pipe, air-inlet and air-outlet pipes are
conveniently arranged around it. By proper connection

DEVELOPMENT, METHODS, AND APPARATUS. 33

with the filling pipe and by the use of valves, one pressure
tank is made to serve four receiving tanks. The upper
cylindrical section is provided with a manhole, and the
tanks are lined first with lead and then with wood to pro-
tect the lead from wear by abrasion. The air pressure
required is from 40 to 50 Ib. Fig. 9 shows a top view, and
Fig. 10 a vertical cross-section of an upright pressure tank,
while Fig. n illustrates the supporting frame. This tank
is somewhat smaller than those used in the Argentine blue
vitriol plants and has one cylindrical section instead of
two. The general arrangement, however, is the same.
The air inlet extends downward along the side, ending near
the discharge pipe, in order to keep any residues near the
outlet in a loose condition and prevent the pipes from
clogging. For this reason it is advisable to have a small
stream of air enter during filling. The residues are rather
heavy and occasionally pack tightly around the discharge
pipe in quite a thick layer, which, on applying the pressure,
would be forced in this compact condition into the dis-
charge pipe and the pipe leading to the purifying towers,
causing them to become clogged.

;<The purifying or refining towers, as shown in the
attached dimensioned sketch, are made of California red-
wood, which makes an excellent material to resist the action
of hot cupric sulphate solution. They are 9 ft. in diameter
at the bottom and constructed of staves 16 ft. long and
4 in. thick, which are well hooped with round iron; the
bottom and top are flat. The towers are firmly fastened
to a strong wooden trestle, which in turn is anchored to a
concrete foundation. This construction is called for to
guard against the oscillating movement of the tanks from
the action of the contained solution, which is set in violent
motion by the ascending air. Inside the tower, about 19
in. above the bottom, the 4-in. lead air pipe enters and is
connected with a perforated 6-in. lead pipe which extends

34 MODERN ELECTROLYTIC COPPER REFINING.

diametrically to the opposite side and is closed at the
farther end. Outside of the tower the air pipe extends
upward to above the top of the tower, and thence down-
ward to the discharge pipe of an air compressor. This
arrangement is necessary in order to prevent the solution
from flowing to the air pump. At the same level with the
air inlet, the 4-in. discharge pipe enters, which is provided
with a hard-lead valve placed close to the outside of the
tower. At about the same level a i-in. steam pipe enters
for heating the charge. The lead steam coil formerly used
has been discarded and the heating is now accomplished
by direct steam. This change was necessary as the lead
coil required frequent repairs, and, moreover, the heating
effect of direct steam is much greater than that of a steam-
heated coil. The solution does not lose in strength through
the condensation of the steam, the evaporation, which is
favored by the 'ascending air, fully equalizing the dilution.
The top of the tower is provided with an 8-in. pipe for the
escape of the vapor and air, and with a 4-in. pipe for charg-
ing the crude solution. An opening in the center sup-
ports a small hopper which is filled with roasted matte,
and by lifting a cone valve the charging is kept under good
control. By the action of the air and the cupric oxide of
the roasted copper matte in the neutral solution, the im-
purities are oxidized and precipitated. The perforated
cones, of which there were three in each tower for the dis-
tribution of the compressed air throughout the solution,
have been replaced by a sufficiently large perforated pipe.
This change simplifies the construction without impairing
the efficiency of the tower. In charging the towers, room
must be left for the increase in volume of the solution which
occurs as soon as the air is supplied. A tower of the new
type can be charged with about 5000 gal. of solution, and
as three such charges can be refined in 24 hours the working
capacity of one tower is 1 5,000 gal. per day. Eight of these

4 Valvepn here,. 4* ValVb HCT«.

'Cast Iron Flange*
^RuMHsr Gasket

FIG. 12. — Hofmann's Tower for Refining Cupric Sulphate Solutions.

36 MODERN ELECTROLYTIC COPPER REFINING.

towers are in use at the Argentine plant. Fig. 12 shows a.
vertical section of a tower of the latest construction. The
air-inlet pipe, which is horizontal within the tank, has only
its lower half perforated to prevent the inflow of matte and
precipitate. The steam pipe was formerly inserted direct
through the wood, but as the latter became affected by the
heat, it now enters through the manhole cover. A similar
effect was noticed with the bolts which passed through the
wood to hold the flanges of the manhole, air inlet, and dis-
charge pipe. In the new construction these holes in the
staves are cut much larger, and neither the frame nor the
bolts are in contact with the wood. This is shown in the
illustration. The two pipes are arranged in a similar
manner. All iron parts on the inside of the tower are
covered with heavy sheet lead.

' ' When the reaction is completed and the solution freed'
from impurities, the charge is drawn off and forced through
a filter press. The tower residues, consisting mainly of
precipitated iron, arsenic, antimony, and some un decom-
posed matte, contain also some basic copper sulphate. To
remove the last-named substance the residues are treated
in a stir tank with a 2.5% to 3% cold acid solution, which
dissolves the basic copper salt, leaving the impurities un-
affected with the exception of iron, which is acted on very
slightly. The refined solution is conveyed to settling tanks
from which the evaporating tanks are supplied.

''The evaporating department furnishes the crystal-
lizing department with about 90,000 gal. of concentrated'
solution daily. To supply this amount an improvement
over the old pan evaporators with under-fire or steam coils,
was requisite, and as vacuum evaporators could not be
adopted, I have introduced an economical and effective
evaporator at Argentine, which is illustrated in Figs. 13
and 14. The principles observed in the construction of
this evaporator are the application of the hot furnace gases

DEVELOPMENT, METHODS, AND APPARATUS. 37

-direct to the heating of the solution and the almost com-
plete utilization of the heat contained in them. The
-apparatus consists of a flat wooden tank with the excep-
tion of a 2 -ft. space at the front end, which is made of
steel, so that the wood will not be in too close proximity
to the furnace. The tank is 65 ft. long, 12 ft. wide, and
2 ft. deep, and is lead-lined, the two ends having much
heavier lead lining than the sides and bottom. It is trav-
ersed longitudinally by 13 six-inch lead pipes and rests
on a wooden trestle-work of a proper height to correspond
with the height of the furnace. At the furnace end in each
lead pipe is inserted a 5-in. iron pipe 4 ft. long provided
-at the outer end with a flange. The iron pipes serve to
protect the lead pipes from immediate direct contact with
the red-hot gases from the furnace; they also make the
connections between the lead pipes of the tank and the
iron pipes of the furnace.

1 ' The furnace is comprised of the fire-place C, the dust-
chamber D, and the heat-distributing chamber D' . At
a proper height in the wall of the distributing chamber
nearest the tank are 13 openings, in each of which is in-
serted a short cast-iron pipe 5 in. in diameter, with a flange
at the outer end. Each pipe is connected with its corre-
sponding lead pipe in the tank by a cast-iron S-shaped
elbow y, which allows the introduction of the compressed-
air pipe E for removing any accumulation of ashes in the
lead pipes of the tank.

' ' An American .underfed stoker is used for the slack-
coal fuel, and affords practically perfect combustion, which
is of great importance, as otherwise the lead pipes would
soon become coated with soot and lose much of their effi-
ciency to transmit the heat to the solution.

' ' The opposite end of the' lead pipes in the tank are
•connected with the brick suction-chamber 0, which in turn
is connected by a galvanized iron pipe R with a suction

38 MODERN ELECTROLYTIC COPPER REFINING.

fan P, the gases being discharged into the underground
flue 5. This flue serves in common to collect the waste
gases from n evaporators, and terminates outside the
building into a brick chimney 40 ft. in height.

FIG. 13.— Pan Evaporator,

FIG. 14. — Pan Evaporator,

; * The top of the pan is closed with a wooden cover and
joists C are placed across the pan about. 5 ft. apart, having
cleats fastened to the lower side, as shown in Fig. 13. The
spaces between the joists are covered with boards resting
on the cleats and pushed close together, but not nailed,
so that the whole or part of the cover can be easily removed.
About 14 ft. from the front end of the tank is a i4-in. suc-
tion pipe L, connected with the main suction pipe M, which
crosses all of the evaporators to remove the water vapors.

DEVELOPMENT, METHODS, AND APPARATUS.

39

This main suction pipe is constructed of wooden staves
kept tight by hoops. The suction pipe L was first made
of lead, but by some unexplained chemical reaction it was
destroyed after a few months of operation. Later a wooden

I

u» .

_j fl_

tr
I

p F ft_

fj nr

Hr

^

/

U"1-~ K

_H £^L

A:

//

j? y/

^^fci

Longitudinal Vertical Section.

Horizontal Section.

tube was substituted, which was made in the same manner
as the main tube. The latter is in connection with a large
fan having the housing and wings of sheet copper and the
shaft and arms of brass. This fan rapidly removes the
vapor from each evaporating tank and by its use the build-
ing, even in cold winter weather, is entirely free from steam.
A wooden stack serves for the discharge of the fan, and the
strength of the exhaust is regulated by a wooden slide N
inserted below the suction pipe L.

40 MODERN ELECTROLYTIC COPPER REFINING.

' ' Close to the end of the evaporating tank, and resting
on the cover, is the lead-lined feed box V, from the bottom
of which is a short pipe or nipple leading into the tank.
The solution supply pipe T, which crosses all the evapora-
tors, is connected with the large supply tanks and serves
to convey the solution to each evaporator by downtakes U.
The outlet of the evaporating tank is in the side near the
furnace end about 4 in. above the hot-air pipe B (Fig. 13).

"The operation is conducted in the following manner:
The pan is first filled to the level of the outlet with the
copper sulphate solution to be concentrated, the fire is
then started and the suction and stoker fans set in motion.
The big copper fan is not started until the solution becomes
hot enough to generate steam. During the operation the
level of the solution is kept at the same height by the occa-
sional addition of new solution through the feed box V.
When it is found by test with a Baume's scale that the
solution near the outlet has attained the desired concen-
tration, a continuous stream of weak solution is allowed
to flow into the tank from the feed box, which starts a
continuous outflow of concentrated solution through the
outlet. The amount of incoming solution is regulated
by frequent hydrometer tests of the solution at the
outlet. The supply of fuel by the automatic stoker being
very regular, the heat of the evaporator is very uniform,
and once having adjusted the proper influx of the weak
solution the outflowing stream will be found of quite con-
stant concentration.

"The object in making the evaporating pan of this
length is to utilize the heat of the fire -gases as much as
possible. The glowing hot gases entering the tubes give
off the main part of their heat to the solution within a
comparatively short distance from the point of entrance
and cause this portion of the solution to boil. In the pas-
sage of the gases through the tubes they gradually come

DEVELOPMENT, METHODS, AND APPARATUS. 41

into cooler regions and^are offered an excellent opportunity
to give off more of their heat to the surrounding solution,
so that when they finally leave the tubes their tempera-
ture is much below the boiling point of the solution. If
the tank had been constructed of still greater length, say
100 or 125 ft., the gases would have left the tubes at a tem-
perature about that of the surrounding air, thus completely
utilizing the heat generated. With the 6 5 -ft. tank, the
pipes at the exhaust end of the tank can be touched with
the hand.

' ' The greater economy and efficiency of this type of
evaporator, as compared with one having a steam coil or
bottom fire, is apparent. The production of steam in-
volves a considerable waste of heat, and in using it to
evaporate liquids, its circulation through coils produces a
large amount of condensed water at a temperature very
nearly 100° C., the heat of which is generally lost. To
evaporate by direct fire under the bottom of a pan is very
inefficient and wasteful, and in the present case, in which
no other metal but lead can be used for the pan, it requires
great care and watchfulness to avoid melting the metal.

"For concentrating chemical solutions which are not
affected by iron, as, for instance, copper sulphate, the new
evaporator described in detail above can be constructed
entirely of iron or steel and at much less cost. The pan
itself, however, should always be placed in a wooden tank
to prevent loss of heat by radiation.

"The outflowing concentrated solution passes into a
6-in. lead pipe and is conveyed to a collecting tank, which
is covered to prevent the cooling of the liquor. At Argen-
tine, one pipe serves to collect and convey the concentrated
solution from n evaporators. From the solution tank
the hot solution is drawn into a horizontal pressure tank,
and is elevated by compressed air to a system of troughs
placed above the crystallizing tanks. The troughs are

42 MODERN ELECTROLYTIC COPPER REFINING.

tightly covered with planks to avoid cooling, which would
cause crystals to form in them. In construction the
troughs are of California redwood, 10X11 in., in sections
of 1 6 ft. The ends of the sections butt together and have
an intervening rubber gasket. The sections are drawn
together by iron flanges fastened to the sides of the trough
a few inches from the end, iron bolts passing through both
flanges. Brass screws are used in making the troughs, as
iron nails or screws would not last. The joints between
the bottom and the sides are coated with a fairly thick
cement, which is made by boiling together waste rubber,
resin, linseed oil, and ferric oxide. The cement when
properly made should be quite liquid when very hot- and
stiff when cold, but never brittle or so hard that it cannot
be kneaded between the fingers; nor should a piece of the
stiff cement become liquid in water at a temperature of
80° to 90° C. The cement is elastic, and, as it never har-
dens, it keeps the joints well filled and overcomes the diffi-
culty which arises from the shrinkage of one board from
another. It has given very satisfactory results in the
Argentine plant, and there has been absolutely no leakage
in the troughs, which in aggregate length amount to nearly
half a mile.

"The crystallizing department has 112 tanks, each of
720 cu. ft. capacity arranged in long rows intersected by
several cross passages. Between each two rows is a track
for transporting the blue vitriol crystals, on either side of
which is a cement channel to receive and convey the mother
liquor. The lead-lined wooden crystallizing tanks did not
prove satisfactory, as the change in temperature caused
by each filling with hot concentrated solution expanded
the lead which did not subsequently contract in cooling;
as a result in course of time the tank lining became wrinkled
and broken and caused leakage and expensive repairs,
The entire floor of the blue vitriol plant is made of cement

UtrULUPMENTt METHODS, AND APPARATUS. 43

in order to collect any leakage that may take place. At
present the tanks are made of concrete, and, though far
superior to the original lead-lined wooden tanks, they do
not come up to expectation because they also are affected
by the sudden change in temperature when filled with the
large bulk of hot concentrated solution. Although con-
structed with walls 20 in. thick, small cracks result, but
leakage can be prevented by plastering a little cement on
the outside of the tank. An experimental tank which has
now been in use for several months seems to answer all re-
quirements. It is built of bricks, having in the center of
the walls a 2 -in. space filled with a mixture of asphaltum
and sand, which extends also from the sides under the
bottom of the tank, thus practically forming a tank by
itself imbedded in the brickwork. When heated by the
sudden filling of the tank with hot solution, the asphaltum
softens, and when gradually cooled it contracts without
cracking.

' ' On the top of each tank are movable wooden frames
supporting numerous strips of lead, on which the crystals
form, as well as on the sides and on the bottom of the tank.
The solution remains seven days in the tank. At the ex-
piration of this time the mother liquor is drawn off and
the crystals removed. Ordinarily 16 tanks are discharged
daily, but during the hot summer months more time has
to be given for the crystallization, and fewer tanks are
discharged and refilled daily.

' The mother liquor is drawn off through a brass tube
close to the bottom of the tank and flows in the above-men-
tioned cement channels in front of each row of tanks direct
to the three pressure tanks placed in a pit. These tanks
elevate the mother liquor to large storage tanks, where it
is mixed with fresh copper sulphate solution from the dis-
solving and refining departments, and is ready to supply
the evaporators. When the crystallizing tank is empty,

44 MODERN ELECTROLYTIC COPPER REFINING. ,

the movable frames with the lead strips and adhering
crystals are lifted by a block and chain and the crystals
knocked off with a wooden paddle. The crust of crystals
from the sides is broken down. Rails are laid in recesses
near the rim of the tanks so that the rails of the two oppo-
site rows of tanks form a track for a hopper mounted on
wheels. The crystals are shoveled with copper shovels
into this hopper, which fills the push-car underneath through
a spout with slide in the center. As the tanks are 6 ft.
deep, the crystals have to be thrown at least 7 ft. high, and
in doing this work some of the crystals unavoidably fall
back into the tank, frequently striking the shoveler. It
was found that this was very injurious to the men, espe-
cially in summer, when they are dressed scantily and per-
spire freely. Their bodies became covered with deep sores,
which were very painful, although not dangerous, and the
men naturally shunned the work and had to be replaced.
Finally this branch of the plant was closed during the
months of July and August.

' ' To overcome this very disturbing feature, I have con-
structed and set in successful operation the device illus-
trated in Fig. 15. On top of the hopper is mounted the
frame KK-wiih a turntable and circular track underneath
which rests on a number of stationary wheels and is kept
in place by the pin P. The object of this turntable is to
make the apparatus available for opposite rows of tanks
by rotation through 180°. The frame K is provided with
a belt elevator E with copper cups, which can be brought
into a horizontal position by means of the shaft F. On the
same shaft are the pullies L and M which drive the elevator
pulley N. The lower end of the elevator is provided with
the boot B, which can be brought down to within a short
distance from the bottom of the tank and into which the
-crystals are shoveled. The power is imparted by an electric
motor on the platform of the frame, which receives the

DEVELOPMENT, METHODS, AND APPARATUS.

45

electric current by an overhead wire with trolley extending
along the rows of tanks. From the time this device was
introduced the men were protected from the injurious effect

of the blue vitriol crystals even during the hot summer
months, as they had to shovel them only a short distance
above the floor.

"The push-cars containing the crystals are wheeled to

46 MODERN ELECTROLYTIC COPPER REFINING.

the sizing and drying department and lifted by a platform'
elevator to the rim of a bin, into which the crystals are-
dumped. From this bin the crystals are fed between a
fast-revolving roll and a plate provided with teeth, which,
breaks the crusts of crystals without injuring the individual
crystals. After passing the rolls the crystals drop into a
small hopper having a short worm conveyor of copper at
the bottom, which feeds a belt elevator provided with
copper cups. The elevated crystals drop into an inclined
trough and are washed by a stream of mother liquor. They
then drop into a hexagonal revolving screen having the
shaft and arms of brass. The screen itself is of maple wood
perforated with holes 0.375 m- in diameter. All crystals-
smaller than 0.375 in., together with the mother liquor, pass
through a second inclined trough to another revolving
screen, which is of sheet copper having o.i25-in. perfora-
tions. The mother liquor, with the very fine crystals,
dirt, and sediment, after leaving the second screen is con-
veyed to an agitating tank and heated by a steam jet to
dissolve the very fine crystals. The resultant solution is
finally sent through a filter press, the clear liquor flowing
to the storage tanks.

"By using mother liquor to wash and screen the crys-
tals, the fine crystals are as clean and pure as those of
larger size. At the present time the blue vitriol crystals
are dried in 10 brass centrifugal machines and conveyed
to the storage bins.

1 ' The crystals, having been obtained from a neutral
solution, are of a very deep-blue permanent color which is
not affected by light except in the direct rays of the sun.
They do not change into a bluish-white powder, which is
the case with crystals made from an acid solution. ' '

The American Smelting and Refining Co. is introducing
the essential features of this method for the purification
of foul electrolytic solutions at its Perth Amboy plant.

DEVELOPMENT, METHODS, AND APPARATUS. 47

As the process requires the electrolyte to be first neu-
tralized, and as this is done by adding to it cupric oxide
(roasted copper matte), the bulk of solution obtained will
increase. This increase may be worked off in two ways:
i, by treating the surplus solution in a separate system of
tanks in which lead anodes and cathodes are used, copper
being removed, while sulphuric acid is set free and is used to
acidify that part of the refined and neutral electrolyte which
goes back to the refinery; or, 2, by making blue vitriol, in
which case, of course, sulphuric acid must be bought for
addition to the refined neutral electrolyte. Special con-
ditions in any given case determine which of these two
methods should be preferred.

Treatment of Slimes.
(By ROBERT L. WHITEHEAD.)

The slimes produced in the electrolytic refining of cop-
per vary in precious metal content from 1500 to 22,000 oz.
silver and from 4 to 200 oz. gold per ton, the copper con-
tained being from 10% to 40%, in the form of metal,
copper oxide, copper sulphide, and copper sulphate, the
last-named combination being due to imperfect washing
of the slimes.

The usual treatment of slimes in large smelting and
refining works equipped with a desilverizing department
is to add the dried slimes in paper bags of 10 or 15 Ib.
capacity to the charge of retort metal on the cupel hearth.
The copper and impurities are oxidized and pass off in the
slag, while the gold and silver is absorbed in the refined
retort metal remaining on the cupel. The copper dross
is treated in a shaft furnace for the recovery of the copper,
antimony, and lead, the copper being regained as copper
matte.

In electrolytic copper refineries the slimes are usually
treated by the sulphuric acid method, which is modified

48 MODERN ELECTROLYTIC COPPER REFINING.

according to the character of the material. In ordinary prac-
tice the wet slimes from the tank-room are dried in a cen-
trifugal dryer having 3o-mesh phosphor bronze screens in
place of the usual filter cloth. The coarse particles of copper
are caught on the screen, while the slimes pass through into
a storage tank. In this treatment about 10% by weight
of the slimes is separated as metallic copper very rich in
silver, which is added to the charge in the anode furnace.
The slimes after settling are transferred to a large tank
lined with i2-lb. lead and equipped with two steam coils
extending its full length. Hot air is forced into the solu-
tion by an injector. Sulphuric acid in the proportion of
1500 Ib. of acid (66° B.) per ton of slimes is then added and
the solution boiled from 10 to 12 hours, which results in
the dissolving of most of the copper, 66% of the arsenic
and all of the bismuth and iron. The supply of steam is
then shut off and the solution allowed to settle. The super-
natant liquor very rich in impurities is siphoned into storage
tanks and subsequently transferred to the evaporators for
the manufacture of copper sulphate crystals (bluestone).
The tank is then filled with water up to the level of the
original sulphuric acid solution, the steam is turned on,
and the temperature again raised to the boiling point.
When this is done an addition is made of the settlings from
the acid-parting kettles, which consist of anhydrous sul-
phate of copper and considerable silver sulphate, and the
contents of the tank are thoroughly mixed. The copper
precipitates metallic silver from the silver sulphate solu-
tion, being itself transformed to copper sulphate, and the
treatment is continued until metallic silver is no longer
produced. Should the silver sulphate be in excess of the
corresponding quantity of copper needed to precipitate its
silver content, a small addition of untreated slimes is made
to supply the deficiency. The slimes are then washed
several times by decantation, transferred to filters, and

DEVELOPMENT, METHODS, AND APPARATUS. 49

washed with boiling-hot water. They are then transferred
to cast-iron drying pans and dried in a furnace, the dried
product being subsequently mixed with sand and soda ash
and melted in a reverberatory furnace capable of holding
100,000 oz. of silver. The dore bars resulting from the
furnace treatment assay from 950 to 960 fine in silver and
from 10 to 20 in gold, the remainder being copper. The
slag from the furnace melting contains 8% or 10% copper
and 300 to 400 oz. silver per ton, the quantity produced
depending upon the richness of the slimes. If the slimes
are very rich the quantity of slag need not exceed 200 Ib.
per ton of slimes treated. The dore bars are placed in cast-
iron kettles and parted by sulphuric acid (66° B.), similarly
to the process in use at the New York Assay Office and at
other government refineries, or they are parted electro-
lytically by the Moebius or the Thum-Balbach process.

The cement silver obtained in acid parting is thoroughly
washed with hot water, placed in a hydraulic press and
pressed into cakes of 1500 to 2000 oz. weight, which are
removed from the press and charged without drying into
a refining furnace of 100,000 oz. capacity. A small quan-
tity of niter is thrown on the metal to remove the tellurium
contained in the silver. When this is accomplished the
molten refined silver is cast into i2oo-oz. molds. The
refined metal varies from 998 to 998.5 in fineness.

The gold is transferred to small parting kettles and
boiled with sulphuric acid (66° B.) to dissolve the remain-
ing silver. When this is accomplished a few lumps of salt-
peter are added to the solution and the boiling continued
for two or three hours to remove the small quantity of
silver still contained in the gold and to coagulate the finely
dissolved gold, which is of advantage in diminishing the
quantity of float gold produced in the subsequent washing.
The gold is then dried, melted under borax, and cast into
bars of 993 to 996 fineness.

50 MODERN ELECTROLYTIC COPPER REFINING.

Generally, in electrolytic copper refineries, the copper
sulphate solution formed by the reduction of the silver
sulphates is added to the copper electrolyte in order to
utilize the free sulphuric acid which is present to the extent
of from 8% to 10%. The impure solution from the slimes
tank is concentrated by evaporation to 42° B. and crys-
tallized, the crystals formed being purified by repeated
solution and crystallization until of marketable purity.
The mother liquor from the crystals contains about 40%.
sulphuric acid, which is utilized by heating in a lead pan
to 60° B. and subsequent cooling in iron pans. During
the cooling, basic salts of iron and copper are separated.
The resultant acid solution is used either in parting the
dore bars or in the first treatment of the slimes. The slags
produced in refining the slimes are treated in several ways:
i. By addition to the slags from the anode furnace, which,
however, has the objection that the resultant copper is
very impure and must be separately treated in the tank-
room. 2. By treatment in a shaft furnace with litharge,
which yields a copper matte and a silver-lead bullion. The
latter is cupelled for silver, the litharge formed being used
to treat another lot of slime slag. 3. By melting the slag
with lead in a small reverberatory, as at the Raritan Copper
Works. 4. By mixing with soda ash and melting in a
reverberatory furnace, which yields a very clean slag and
a very base bullion. This slag is sold to lead smelters, as
it contains less than 60 oz. silver per ton and practically-
all of the antimony and tellurium of the original slimes.
The base bullion is treated by adding small quantities to
the regular charge of the softening furnace. The last-
named method is the one used at the present time by the
Seattle Smelting and Refining Co., at Seattle, Wash., in the
treatment of the slimes produced by the Amalgamated
Copper Co. 's plants at Great Falls and at Anaconda, Mont.

DEVELOPMENT, METHODS, AND APPARATUS.

RESUME OF MODERN PRACTICE IN ELECTROLYTIC WORKS.

1. Anodes: Precious metal bearing copper, refined to as
high a percentage as is commercially practicable, say 96%
to 99% Cu.

2. Cathodes: Thin sheets of electrolytic copper, de-
posited upon and stripped from greased lead or copper
plates.

3. Electrolyte: Solutions containing not less than 12%
and not over 20% bluestone (CuSO4+5H2O) and from
4% to 10% free sulphuric acid. It is very important that
the constantly decreasing acidity and the constantly in-
creasing copper contents of the electrolyte be maintained
within these limits. A small quantity of salt or hydro-
chloric acid is always added to hinder any possible solu-
tion of silver and to prevent "sprouting" or brittleness
of the cathodes. Ammonium sulphate is sometimes added
when considerable arsenic is present.

4. Temperature: Heating the electrolyte up to between
40° and 50° C. is advantageous, because it decreases the
electrical resistance of the solution and increases the ten-
sile strength of the depositing copper. It is essential to
maintain the temperature as evenly as possible at the point
fixed upon, and to avoid appreciable differences in tem-
perature between the upper and lower portions of the
solution.

5. Current Density: From 4 to 45 amperes per square
foot of cathode surface, according to the cheapness of
power, the grade of the anodes in silver and impurities, and
the purity of the electrolyte.

6. Voltage: o.i to 0.3 V., according to the current den-
sity, composition of the anodes and electrolyte, tempera-
ture, structure of the electrodes, and the distance the
latter are placed apart.

$2 MODERN ELECTROLYTIC COPPER REFINING.

7. Products of Refining:

(a) Cathode copper (99.86%' to 99.94% Cu), the

yield being from 97% to 99% of the copper
contained in the anodes refined (barring the
anode scrap), and i% to 3% of the copper
being recovered as bluestone.

(b) Fine silver, -}

(c) Fine gold, I obtained from

(d) Base bullion, containing anti- | t1he anode

1 j_ n • slimes,

mony, arsenic, and tellurium, J

(e) Bluestone, \ obtained both from
(/) Impure arsenical copper, j- the anode slimes
(g) Arsenious acid, ) and the electrolyte.
(h) Nickel vitriol, obtained from concentrated elec-
trolytic solutions.

TABLES GIVING OUTPUTS AND OTHER DATA OF ELECTROLYTIC
COPPER REFINERIES.

The subjoined carefully compiled statistical tables show
that the world's average production of electrolytic copper
is now about 883 short tons daily, of which 764 tons, or
86.5%, are supplied by the United States. Of the balance
of the world's production of about 119 tons daily or ap-
proximately 13.5%, Great Britain produces a little over
8.8 %, Germany about 2. 75 %, and France a little over i .6 %.

The United States now produces at the enormous rate
of 278,860 tons of electrolytic copper, which at $260 per ton
is worth $72,503,600, annually. The by-product recov-
ered daily contains about 74,100 oz. silver and 948 oz.
gold, which equals an annual output of over twenty-seven
million ounces of silver, valued at nearly $13,000,000, and
more than three hundred and forty-six thousand ounces
of gold, valued at $7,152,233.

According to the Treasury Bureau of Statistics, the

DEVELOPMENT, METHODS, AND APPARATUS.

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DEVELOPMENT, METHODS, AMD APPARATUS. 55

•copper exports of the United States, chiefly consisting in
electrolytic copper, for the year 1902, alone represented a
value of $45,485,598, as against $33,534,899 in 1901, and
were only exceeded in value by the country's exports of
manufactures of iron and steel and of mineral oils.

There are now in active operation, or ready to be placed
in commission, 33 electrolytic copper refineries in the
world, not including the plant of the Osaka Electrolytic
.Refining Co., now being constructed at Osaka, Japan.

CHAPTER II.

DESCRIPTION AND VIEWS OF ELECTROLYTIC COPPER
REFINING WORKS.

THE present practice and appliances used in electro-
lytic copper works are described in detail in the following
pages, and the characteristic arrangements of plant and
the equipment are illustrated, wherever it has been possi-
ble to obtain views, in order to give the reader a fair and
comprehensive conception of the present status and mag-
nitude of electrolytic copper refining.

The works are grouped under the heads of the coun-
tries in which they are situated, starting with the United
States and followed in order by Great Britain, Germany,
Austro-Hungary, France, and Russia, and under each head
the refineries are considered in the order of their relative
capacities.

Not including the plant of the Osaka Electrolytic
Refining Co., in Japan, which is reported to be under
construction, they embrace a total of 33 refineries.

A. UNITED STATES.

I. The Raritan Copper Works.*

By LAWRENCE ADDICKS.

The Raritan Copper Works, in its location at Perth
Amboy, N. J., possesses unusual advantages for the econom-

* Taken from The Mineral Industry, vol. ix, by kind permission of the
author and publishers.

56

' I I T

DESCRIPTION AND VIEWS OF REFINING WORKS. 57

ical refining of copper. The transportation facilities are
such that the most favorable freight rates, both domestic
and foreign, are obtainable and the proximity of New
York allows the lowest prices on supplies to be procured.
Spurs from the Pennsylvania Railroad, the Central Rail-
road of New Jersey, and the Lehigh Valley Railroad run
directly into the yards of the works, and a private line of
lighters is maintained from the company wharf, a short
distance from the furnace building, to New York by way
of Staten Island Sound. The lighters afford a cheap means
of placing the refined product alongside outward-bound
vessels at New York and the competition among the differ-
ent railways precludes the possibility of the company ever
being placed at the mercy of a single line. There is suffi-
cient depth of water at the wharf to allow large vessels
to load and unload directly at the works should it be found
desirable.

The plant was designed for a maximum monthly produc-
tion of from 10,000,000 to 12,000,000 Ib. of cathode copper
in the tank-house and from 15,000,000 to 18,000,000 Ib. of
refined copper from the furnaces. The output of precious
metals varies with the character of material treated, but
may be stated as 300,000 oz. of silver and 5000 oz. of gold
per month. A very wide range of raw material is treated,
about the only requirement being that the copper content
shall be equal to that of good blister copper. The excess
of furnace capacity over tank-house capacity makes it
possible to treat a considerable quantity of outside cathodes.
Anodes from outside sources also are more or less handled.

General Plan. — The general arrangement of the build-
ings and railroad connections is shown on the accompany-
ing ground plan (Fig. 16), which is self-explanatory. The
standard-gauge tracks connecting with the several railway
systems are indicated by heavy lines, while the narrow-
gauge tracks of the industrial railroad, as it is called, are

MODERN ELECTROLYTIC COPPER REFINING.

MAP OF THE

RARITAN COPPER WORKS

Perth Amboy, N. J.

Dec. 1900

Office

Sulphate Bld'g
C Silver Bld'g
D Smithy
E Machine Shop
F Stores
G Power House
H Pump House
I Tank^Hous*
J Furnace House
K Lavatory
L Coal Storage
M Engine House
N Furnace House
O Blast Furnace
P Storage Bld'g
-Industrial R.R.
Standard Gauge R.R.

FIG. 16.

DESCRIPTION AND VIEWS OF REFINING WORKS. 59

distinguished by light lines. This railroad is equipped with
two locomotives and a large number of iron flat cars of a
capacity of 10 tons each, and it binds all the buildings
together with a network of tracks. All incoming copper
bullion is unloaded from the freight cars directly on these
small ones and taken to the storage building, where it is
weighed, without being removed, in drafts of about 15,000
Ib. Ample yard tracks are provided, so that such material
as is not for immediate use may be temporarily stored on
the cars, thus avoiding subsequent rehandling

The greatest care is- used to obtain accurate weights.
Two scales are provided and all material is weighed twice.
Furthermore there are two weigh-masters who keep inde-
pendent records, while a third man checks the number of
pieces. The scales were installed by the Fairbanks Co.,
and their representative makes weekly visits to the works
to examine and adjust them. For further reassurance
that they are in perfect adjustment a car loaded with
standard weights is run on several times a day. Heavy
sampling drills and a coffee-mill are also provided in the
storage building.

The works proper, shown by the dotted fence line on
the map, cover about 45 acres. The various buildings are
grouped about the tank-house as a center and all are so
arranged that future extensions may be made with the
least possible expense and inconvenience. A coal- storage
building is conveniently placed near the power-house, and
a coal trestle to supply the furnaces is located at the oppo-
site side of the grounds.

The general use of steel construction throughout the
plant, the thorough fire protection, and the universal appli-
cation of labor-saving machinery are noteworthy features.
The three furnace buildings are entirely of metal and need
no special fire protection. The tank-house has a steel
skeleton with brick curtain walls and is protected by a

60 MODERN ELECTROLYTIC COPPER REFINING.

thorough system of automatic sprinklers and eight inside
hose connections. The other main buildings are protected
by sprinklers. The coal- storage building is provided with
a number of thermostats buried in the coal heaps. For
fire service an Underwriter pump of a capacity of 1000 gal.
per minute is kept in constant readiness to be thrown on
full head at an instant's notice. The water supply con-
sists of an 8-in. city main, a 24-in. line from the river, two
wells, and a reservoir. In an emergency a portion of the
regular pumping system may also be pressed into fire ser-
vice. A number of fully equipped hose houses and a
thoroughly organized fire department complete the pro-
tective measures.

In passing it may be of interest to state that the ground
was broken for the erection of the first building on August
i, 1898, and the current was turned on in the tank-house
March 23, 1899, an interval of less than eight months.

Office Building. — The office building is two and one-half
stories high and about 75X90 ft. Here are located the
general offices, the drafting-room, and the chemical and
physical laboratories. The chemical laboratory is divided
into three rooms, the assay-room, the balance -room, and
the general laboratory. The assay-room is equipped with
three gas muffie furnaces, a gas crucible furnace, a rolling
machine, a cupel machine, pulp balance, bucking-board, etc.
The balance -room contains a set of five gold, analytical,
and pulp balances, supported on a special foundation to
avoid vibration. The general laboratory, which is about
20X35 ft., is furnished with the customary gas, water,
electricity, suction, hoods, etc. A unique feature is the
use of electric heaters as hot plates in the hoods. On the
opposite page is tabulated the routine work of the labora-
tory.

There are also special determinations occasionally made,
as analyses of coal, water, etc., and the copper, arsenic,

DESCRIPTION AND VIEWS OF REFINING WORKS.

61

and antimony contents in wire bars in the event of a low
conductivity report by the physical laboratory, but these
are of comparatively infrequent occurrence. For details
of the methods of analysis employed, the reader is referred
to the article on copper analysis by Titus Ulke,* the meth-
ods there described agreeing closely with those employed
here.

Frequency.

Material.

Determinations.

Twice daily

Blast-furnace slag . .

Cu

r Electrolyte (a)

Cu, Acid, Sp. Gr.

Daily. .

Copper bullion

Cu, Ag, Au.

r» A A

Anodes

Blast-furnace pigs

Cu, Ag, Au.
Cu Ag Au

Cathodes

Cu Ag As Sb.

Electrolyte

Cu As Sb, Cl.

Slimes

Cu Ag, Au.

Weekly

.

Silver slabs

Ag, Au.

Silver slag

Cu, Ag, Au, Pb

Fine silver

Ag.

Au.

Blister slag '.

Cu, Ag, Au.

Refinery slag

Cu

Occasionally

Blast-furnace charge. . . .
Cement copper

Cu, Ag, Au, SiO2, Fe, CaO.
Cu, Ag, Au.

(a) Performed at laboratory in tank-house, but included here for the sake of completeness.

The physical laboratory is equipped with a Queen .con-
ductivity bridge, a 6ooo-lb. Riehle tensile machine, and a
5oo-lb. Riehle torsional wire -testing machine. Daily tests
are made of the conductivity of each lot of copper produced
by the refining furnaces, whether ingots, wire bars, or
cakes. The bridge is checked each day against a standard.
No. 12 B. & S. annealed wire is used for these conductivity
tests ; it is drawn in the shops from small sample bars taken
from each charge. The written approval of the physical
laboratory is required before any lot is allowed to leave
the works.

* Engineering and Mining Journal, Dec. 16, 1899.

62

MODERN ELECTROLYTIC COPPER REFINING.

Power-house. — The power-house is of modern design,
built of brick and steel. It is divided by a central longi-
tudinal brick partition into boiler- and engine-rooms. The
general arrangement is clearly shown in the sectional draw-
ing (Fig. 17). The building is thoroughly fireproof, and
in this connection it may be noted that the engine-room
floor is constructed on the Ransome system of cement

FIG. 17. — Cross-section of Power-house.

throughout. A basement 9 ft. in the clear is provided
beneath the engine-room.

The boiler-room contains the boiler equipment only,
consisting of eight 400-H.P. and two 200-H.P. Babcock &
Wilcox water-tube boilers. These are set in pairs, with a
passageway between each battery for the convenient blow-
ing of tubes and cleaning of dust-chambers. The furnaces
are of the Murphy automatic-stoking type. Directly be-
neath them is an ash-tunnel running the length of the
building; through this tracks are laid for a side-dumping

DESCRIPTION AND VIEWS OF REFINING WORKS. 63

steel car. Under each furnace is a steel hopper the dimen-
sions of which correspond to the capacity of the car, fur-
nished with a sliding gate at the bottom. When the car
is placed in position, this gate is opened, the ashes are
dumped, and the car is pushed through the tunnel to a
hydraulic lift at the south end of the building, raised to
grade and run out to the lowlands for dumping. Over
the furnaces is a coal hopper of 393 tons capacity, extend-
ing the length of the boiler-room, with a discharge nozzle
over each feeding magazine. At the end of each nozzle
is a swinging gate with lever and rod connection extending
down to the front of the furnaces within easy reach of the
firemen. Directly beneath each nozzle is hung a heavy
sheet-iron chute of 13 cu. ft. capacity, at the lower end
of which is another swinging gate controlled with lever
and rod as before. These chutes and levers are shown in
the photograph of the boiler-room (Fig. 18). There are
two furnaces to each boiler and one double and two single
magazines to each pair of furnaces. The upper gate levers
are connected to a counter in such a manner that the num-
ber of chutes of coal used for each boiler is registered, thus
allowing the coal consumption readily to be computed.

The coal is handled mechanically throughout its entire
course, being dumped from the cars in which it is shipped
into a hopper, then taken by a drag conveyor, screened,
the coarse lumps crushed, recombined with the screenings,
and elevated to the tower of the coal-storage building just
south of the power-house. From this tower it may be con-
veyed either to the bins of the coal-storage building or
directly to the hopper in the boiler-room. The space
beneath each boiler where the grates and ash-pits are
usually placed is used entirely as a combustion-chamber
.and for the collection of the heavier ash and soot which is
carried through from the furnaces. The smoke-flue is built
-as a tunnel parallel with the ash-tunnel, and leads to a brick

64 MODERN ELECTROLYTIC COPPER REFINING.

stack 175 ft. high, at the south end of the building. There
are individual dampers arranged for hand control and a
main damper governed by a Spencer damper-regulator.
The north boilers are used for electrolytic service, while
the three south boilers are used independently for supply-
ing steam for solution heating in the tank-house and for
operating the general service -pumps and the light and
power engines. These latter boilers are operated at 125-
Ib. and the former at i7o-lb. gauge pressure.

The illustration of the power-house (Fig. 17) and the
photograph (Fig. 19) show the general arrangement of the
main piping. The steam -header is shown in section near
the division wall. The valves allow a boiler to feed its own
engine directly or to supply the- main header in parallel
with the other boilers as occasion may demand. With this
system it is possible to repair the entire steam-header with-
out interruption of the service or in turn to repair any one
of the steam mains without discontinuing the service for
more than one unit. A separator is inserted between the
header and each throttle -valve. The engines for the elec-
trolytic service, five in number, are vertical, cross-com-
pound, and condensing, running at 150 revolutions per
minute, each direct connected to its generator. The dif-
ferent generators vary slightly in capacity, but the largest,
built by the General Electric Co., deliver 4500 amperes at
an efficiency of 93.5%. The engines for supplying light
and general power are horizontal, tandem -compound, run-
ning at 265 revolutions per minute, with generators direct
connected. All of the engines were built by the Ball &
Wood Co. Efficiency tests of the vertical Corliss engines
showed an economy of from 13.4 to 13.7 Ib. of steam per
I.H.P. per hour. The exhaust piping of the engines leads
from the gallery down past the generators, through the
floor to Berryman feed-water heaters and thence to Bulkley
ejector condensers. Each engine has its independent in-

DESCRIPTION AND VIEWS OF REFINING WORKS. 65

termediate heater and condenser. The boiler feed-water
passes from the city main through a meter in the north
end of the power-house basement into a main running the
full length of the building and tapped at each of the Berry-
man heaters. A parallel main receives the discharge from
the heaters and carries it to a Cochrane open heater set
directly above the feed-pumps at the south end of the build-
ing. The exhausts from the light and power engines and
boiler-feed and general service pumps are taken into this
heater. The Berryman heaters deliver the feed-water at
123° F. and the Cochrane heater raises this temperature to
about 210° F. The feed- water is carried into the feeding
main by duplex, tandem-compound Snow pumps. The
branch for each boiler is provided with a Worthington hot-
water meter and a specially graduated throttling-valve.
Suitable thermometer wells and boiler oil injectors are
placed in each boiler feed-pipe within easy reach and con-
trol of the engineer; the feed-pipes do not pass through
the division wall into the boiler-room until after leaving
the hot-water meters. A valve in the feed-line is also
placed in the engine-room so that the engineer may con-
trol the supply of water if he so desires. Water-column,
gauge-cocks, and steam-gauge for each boiler are placed
along the division wall on the engine-room side, the piping
leading directly through the wall to the drums of the boilers.
There are also draft and pyrometer tubes in this wall at
the rear of each boiler. In this way the engineer has the
boiler performance entirely under his observation and con-
trol without going into the boiler-room.

At the extreme south end of the power-house is the
pumping plant. It consists of two centrifugal pumps
which take water for condensing purposes from a well fed
by the river, two 24 -in. stroke 3,ooo,ooo-gal. compound
duplex pumps which are used expressly for supplying bosh
water to the copper furnaces on a return system, including

€6 MODERN ELECTROLYTIC COPPER REFINING.

the reservoir, a 35o,ooo-gal. compound duplex pump used
for supplying water for general purposes about the works,
and the simple duplex Underwriter pump before men-
tioned, which ordinarily supplies a number of hydraulic
lifts. Two Westinghouse 9-5-in. air-pumps supply air at
70 Ib. pressure for cleaning generators, handling oil, acid,
«tc., and for operating pneumatic hoists.

The oiling system for the entire plant is a modification
of the usual gravity system. A reservoir is placed at one
end of the engine-room directly beneath the roof and is
connected by suitable piping with the sight-feed and con-
trolling valves which distribute oil to the various bearings.
All of the valve-motion mechanism is lubricated with grease
from compression cups. The engines are specially fitted
with oil-ways, collecting-rings, and guards, and the waste
oil is carefully caught and piped to a fire-proof oil -room
in the basement In this oil-room there are two sets of
filters and a receiving-tank from which the overhead tank
is periodically filled. Compressed air is used for refilling
the overhead gravity tank and a counter attached .to a
float registers the number of tanks of oil used. The valves
and pistons of the engines are lubricated by means of Ster-
ling, Jr., pumps There is a pump connected with each
admission valve, operated by the exhaust- valve mechan-
ism in such a manner that a minute quantity of oil is injected
into the steam just prior to its admission to the cylinder at
each stroke.

Tank-house. — The electrolytic plant is in a single build-
ing approximately 200 X 600 ft. The use of a steel skeleton,
carrying the loads, and brick curtain walls, and the 7 to 8 ft.
of head room in the basement are noteworthy features in
the construction. The type of building is show^n in the
illustration (Fig. 20) and the photograph (Fig. 21). Thor-
ough lighting and ventilation are supplied by an immense
number of windows, a large high monitor, and a series of

DESCRIPTION AND VIEWS OF REFINING WORKS.

ventilating skylights. The main floor is made very heavy
and can support a loaded train in connection with the indus-
trial railroad. The basement is floored with a 6-in. layer

FIG. 20. — Cross-section of Tank-house.

of tar concrete which has proved very satisfactory in with-
standing acid and trucking. There is a 5 -ply tar and gravel
roof, the planking of which is carried on steel trusses. The
general ground plan is shown diagrammatically in Fig. 22.

150
Tanks

50
Tanks

PcjaP

50
Tanks

50
Tanks

GROUND PLAN

Q, OFFICE. L, LABORATORY. P,P, PUMPS. TOTAL NOMBtR OF TANKS, l»600t

FIG. 22. — Tank-house.

An office and laboratory are provided at one end while the
main-floor space is given up to the 1600 depositing tanks.
The liberating tanks, 32 in all, are in small additions built
on the north side. Emery-wheels, punches, and shears
are placed along the end walls, and the solution pumps
are situated in the main longitudinal aisle. Tunnels are
provided from the basement to the power-house and silver
buildings. Four electric cranes equipped with a special
appliance for handling electrodes run the length of the
building, each commanding 400 tanks. For convenience

68 MODERN ELECTROLYTIC COPPER REFINING.

in description the tank-house may be considered, first,
from the point of mechanical operation, second, from that
of electrical supply, and third, from that of distribution
of electrolyte.

Operation. — The regulation multiple system is in use,
the tanks being electrically in series and the electrodes in
each tank in parallel. This necessitates the apportionment
of a certain number of tanks as cathode-forming or * * strip-
ping " tanks. These, 180 in all, are divided between the two
end sections, giving ready access to the special machinery
along the end walls. The cathodes in these tanks are
rolled plates of pure copper, 0.156 in. thick, the surfaces
of which have been smeared with tallow which is kept fluid
in steam- jacketed pots. These are used as a basis on which
to form the thin cathode sheets for use in the regular de-
positing tanks. The edges are protected from deposition
by grooved wooden strips * which are slipped on before the
plates are put in position. After remaining in the strip-
ping tanks 36 hours, they are removed, the wooden edges
knocked off, and the thin sheet of deposited copper peeled
from each side of the plate, the presence of the tallow hav-
ing prevented any firm adhesion of the surfaces. The
entire work of removing, stripping, and replacing a plate
occupies but a few moments. The thin cathode sheets are
taken to the shearing and punching machines, where two
thin copper loops are riveted on. They are then flattened
carefully out by beating with wooden paddles and hung
in the depositing tanks from copper rods which are flattened
at one end to prevent rolling. At the end of seven days,
the cathodes are removed, a tankful at a time, by the
crane and dumped on the floor in one of the main cross
aisles. The rods are taken out and the cathodes piled on

* These are no longer in use, as their purpose is better served by perfor-
ating or grooving the plates near their lateral and bottom edges and filling
these perforations or grooves with a suitable insulating material. — TITUS Ui*KB.

DESCRIPTION AND VIEWS OF REFINING WORKS.

69

cars of the industrial railroad to be taken to the furnaces.
The shape and method of support of the electrodes may be
seen in the drawing illustrating the details of tank con-
struction (Fig. 23). The anodes are brought into the tank-

copper

Glass Block

"PoFcelain Block

SIDE ELEVATION

CROSS SECTION, SHOWING
METHOD OF ANODE AND
CATHODE SUSPENSION

« n

"1

—

v

m t^ v^ ^

jj

1

|

— Cathodes
0

!

~ ,

&4 : , Jp

r

_

^Copper. Plate
0
^Anodes

j

•

y & £, ^

m ka

PLANi SHOWING ELECTRICAL CONNECTIONS BY THE DASHED LI N.ES

FIG. 23. — Details of Tank Construction

house on cars and hung in frames made of structural iron,
which are designed to place the anodes in the same relative
position that they are to occupy in a tank. When a suffi-
cient number to fill one tank have thus been hung, the
traveling crane picks them up without touching the frame
and carries them to the tank in question, lowering them
directly into place without any intermediate handling by
the men. The crane is shown in action in the photograph
of the tank-house (Fig. 21). Each anode weighs about
400 lb., and as there are 22 to a tank, the load weighs
between 4 and 5 tons. In addition to the cranes, runways
are provided over each separate row of tanks, along which
trolleys travel that carry differential blocks for the con-
venient handling of single electrodes. These find constant

70 MODERN ELECTROLYTIC COPPER REFINING.

use in connection with the stripping tanks. The anodes
remain in the tanks 43 days on an average, when they are
taken out, scrubbed, and sent back to the anode furnaces
as scrap. By careful reworking in the tanks all anodes
the condition of which, on removal, warrants the labor of
rehandling, the percentage of this scrap returned to ,the
furnaces is kept down to about 9%. The slimes are re-
moved but once in three months. Then the tanks are
emptied of solution one at a time by means of steam siphons.
The slimes are sluiced through an outlet in the tank bottom
into barrels mounted on trucks in the cellar below.

Electrical Supply. — Electrically the tank-house is divided
into units of 400 depositing and 8 liberating tanks each.
These 408 tanks are all connected in series and form the load
of one of the large generators in the power-house. There
are 22 anodes and 23 cathodes in multiple in each tank.
The arrangement of tanks in pairs with cross connections,
as shown in the diagram of electrical connections (Fig. 23),
combines convenience in handling with economical use of
copper in conductors and minimum impairment of effi-
ciency in event of short circuit occurring between a pair
of electrodes. The main conductors are 1.25X4 in. bar
copper, carrying about 4000 amperes. The connections
between paired tanks are made by means of strips of copper.
All contact resistances are kept as low as possible by the
liberal use of emery. This gives a current density of 15
amperes per square foot of cathode surface, the end elec-
trodes being credited with but one active side each. Dur-
ing cleaning, a tank is short circuited by use of the wedge
or key shown in the drawing (Fig. 23). The conductors
are supported by five clamps on each tank, three of which
are carried down to the stringers below. The tanks are
insulated from the building with the greatest care, glass
blocks being used under all supports, and the main floor
having a clearance of several inches. Bulging at the sides

DESCRIPTION AND VIEWS OF REFINING WORKS. 7*

is prevented by the alleyway floors and iron braces on the
outside tanks.

Distribution of Electrolyte. — Each of the electrical units
mentioned above is divided into two circulations, each con-
sisting of 200 depositing tanks, four liberating tanks, a
solution well, and a pump. Thus there are in all eight
entirely independent circulations. The ground plan of the
tank-house (Fig. 22) shows the way in which these units
are placed in the building, each pump supplying four of
the 5o-tank squares as indicated by the arrows. These
units are terraced in each direction as shown in the diagram
(Fig. 24). The solution is carried from the supply-box

U Well

FIG. 24. — System of Circulation of Electrolyte.

at the pump along a main and supplies the tiers in multiple,
so that each ounce of solution does duty in five tanks in
series before being returned to the solution well to be
pumped up again. The rate of circulation is controlled
by the throw of the pump, which is of the plunger type;
at the rate maintained, all the solution in a tank is replaced
about every hour and three-quarters. The distribution is
governed by valves at the crest of each tier. The spouts
from tank to tank take the solution from the bottom of one
tank and deposit it on the top layer of the next, thus main-
taining a uniform density. The tanks are lined throughout
with 8-lb. lead, the launders with 6-lb., and the solution well
with i4-lb. A certain portion of the solution is taken from
the supply-box at the pump through a small pipe leading

MODERN ELECTROLYTIC COPPER REFINING.

to the liberating tanks and thence returned to the well.
These liberating tanks serve to regulate the copper content
of the electrolyte. They are identical with the depositing
tanks in construction and operation except that lead anodes
are used. Their location, in small additions to the main
building with special ventilators, prevents the excessive
contamination of the tank-house atmosphere due to the
fumes here given off. The solution is maintained at a mean
temperature of 120° F. by steam coils in the wells. On
those circulations which include stripping tanks the solu-
tion is cleansed of tallow by being forced under an inverted
dam. The tallow is removed from time to time at the
entrance side of the dam where it collects. A circulation
may use the same solution a number of months before it
becomes sufficiently foul to give any trouble; when this
finally occurs a portion is run off into a storage well in the
cellar and replaced by fresh solution. When a sufficient
quantity of foul solution has accumulated in this well it is
run over to the sulphate building; its subsequent treat-
ment is described later in this article. The following par-
tial analyses of a working solution and the copper deposited
from the corresponding bath are taken from a regular assay
report of recent date:

Cu.

%

As.
%

Sb.

%

Ag.
Oz. per
Ton.

Free

Hfv

CuSO4

sH%a

Sp.
Gr.

Mean
Temp.

Electrolyte

4- 25

I 1 60 1

O O2QS

Q. 12

l6.7Q

1 ,22O

II7°F.

Cathode. . . .

99-94

0.0013

0.0015

0.30

Solutions more impure than this are constantly in use.

When slimes are to be removed, the tanks in question
are cut out of service, the circulation being stopped by clos-
ing the valves on the individual supply pipes at the crest
of the cascade, and the current being shut off by short cir-
cuiting. The traveling crane then removes the anodes,

DESCRIPTION AND VIEWS OF REFINING WORKS. 73

a tankful at a time, and similarly the cathodes. The solu-
tion in the lowest pair of tanks is then emptied into the
launder through a steam siphon. The plug in the bottom
of the tanks being pulled out, the slimes are sluiced out with
the residual few inches of solution into the slime barrels in
the cellar below. The plug is replaced and the solution in
the next pair of tanks siphoned into the pair just cleaned
and the new electrodes placed in position by the crane,
and so on. The circulation is stopped in 10 tanks at a time
while cleaning, the current, however, being shut off from
but four at a time. The slime buggies are pushed through
the tunnel into the basement of the silver building, and
their treatment will be described further along in this
article.

Furnace Buildings. — There are three furnace buildings
shown on the ground plan (Fig. 16) at J, N, and O. The
first is about 80X600 ft. and contains four 5o-ton anode
furnaces and five refining furnaces of the same capacity.
The second building is 80 X 200 ft. and contains four
25-ton refining furnaces. The third building is the blast-
furnace building, which will be considered under a separate
heading. These buildings have steel skeletons, corru-
gated-iron sides and roof, and checkered cast-iron floor-
plates. The nine 5o-ton furnaces are equipped with mechan-
ical conveyors for the rapid casting of anodes in the case
of four furnaces and wire bars in the case of the others.
One 2 5 -ton furnace is furnished with a special conveyor for
casting cakes. The three others are used for making ingots
and molds by hand ladling and one of them has a pit for
making shot copper. A section of the large furnace build-
ing is shown in Fig. 25 and plan and sections of a 5o-ton
furnace are shown in Fig. 26. The charging side of the
building being next to the tank-house allows a ready hand-
ling of cathodes to the refining furnaces. The tracks of
the industrial railroad run the length of the building on both

74

MODERN ELECTROLYTIC COPPER REFINING.

sides. On the pouring side there is a traveling crane and
a number of small jib cranes. At one end of the building
is a ladle-drying furnace where the clay linings of ladles are
quickly and cheaply baked.

The refining process presents nothing worthy of special
note, the customary rabbling and poling being followed.

. FIG. 25. — Section through Furnace Building.

The blister or anode furnaces pour a daily charge of up
to 150,000 Ib. each, which has been mixed to produce
anodes containing from 100 to 120 oz. of silver per ton.
The daily output of the wire-bar furnaces reaches 120,000
Ib. each.

The mechanical conveyor of one of the wire-bar furnaces
is shown in the photograph (Fig. 27). The molten copper
is received in a ladle placed directly below the tap-hole
launder, and is thence delivered to molds brought succes-
sively into position by a table conveyor. The ladle is of
sufficient size to hold the copper which flows from the spout

DESCRIPTION AND VIEWS OF REFINING WORKS.

75

while the conveyor is in motion. The stream from the
furnace is governed by bits of wood thrust into the spout.
The ladle, which is of iron, clay-lined, is raised and lowered
by a hydraulic piston controlled by the ladler. The cop-
per in the ladle is protected from oxidizing influences by
a layer of charcoal. The conveyor consists essentially of
a series of copper molds carried by an endless chain of link

LONGITUDINAL SECTION

CROSS SECTION OF
FIRE PLACE

TT i I I I

PLAN

FIG. 26. — Details of the Fifty-ton Copper-refining Furnace.

work. The system is moved by a lo-H.P. series railway,
motor governed by the customary controller and geared
to the driving head at one end of the chain. The molds
proper are mounted on four-wheel carriages, the two pairs
of wheels of which travel on pairs of rails of different gauge,
so that a mold depends for its inclination from the horizontal ~
upon the relative positions of the two sets of rails at the
point of travel in question. The longitudinal axis of the
mold is in line with the issuing stream of copper, but the /
line of passage of the mold, when the conveyor is in motion,
is at right angles to this stream.. The first condition per-

76 MODERN ELECTROLYTIC COPPER REFINING.

mits the mold to be rapidly filled without splashing or
causing any pinching from unequal heating, while the
second condition prevents the " heeling up" of the still
liquid metal at the end of the mold, which would result
from the long waves produced, were the motion in the
other direction. The molds now filled are lowered hori-
zontally, by means of the double rails, into water boshes,
where they remain long enough to cool without becoming
totally chilled. As the entire mold with casting in place
is submerged, unequal contraction and consequent trouble
in delivering true castings is avoided. As the conveyor
proceeds, the link work carries the mold and contained
casting out of the water and suspends them vertically for
a moment to drain off the surplus water; it then moves
over the driving head and dumps the finished wire bar on
guides which lead to a small truck. (In the photograph
the steam may be seen rising from the water bosh and the
mold which is draining is clearly shown. As the picture
was a time exposure it was necessary to stop the flow of
metal from the launder.) The mold under consideration
now passes beneath on the return trip, where it is daubed
with bone-ash wash by an attendant and thoroughly dried
by a current of hot air. The attendant in the pit marks
on the inside of the mold the exact height to which it should
be filled to give a bar of the standard dimensions.

The use of this casting device not only reduces the skilled
labor to a furnaceman and his helper, but allows charges
of 120,000 Ib. to be poured in from four and a half to six
hours, depending on the size of the bar made, frequently
without a single bad casting.

The conveyors for the anode furnaces differ in detail but
not in principle. The bosh is omitted as the appearance
of the casting is no longer an object and the casting itself
is so shaped that it cools sufficiently for rough handling
without the use of water. The final cooling is usually

DESCRIPTION AND VIEWS OF REFINING WORKS. 77

accelerated by a thorough wetting down with a hose after
the anodes are stacked up. The anode is prevented from
sticking in the mold by a pin, which automatically forces
it out from below, and is delivered on a pair of arms very
much as a sheet of paper is delivered from a jobber's print-
ing-press. A pneumatic hoist now takes it with a pair of
tongs and places it on a car specially designed for handling
hot material. Each of these anode conveyors delivers
without special effort a charge reaching sometimes . over
150,000 Ib. in three hours. This figure is from actual work-
ing results and not a special estimate. In the cake-copper
conveyor a reciprocating train is substituted for the endless
chain and unloading cranes are provided at each end, the
cakes being taken off at one end of the train while the molds
at the other end are being filled from the ladle situated
midway between the cranes. The unloading device con-
sists of two pneumatic hoists, one small and one large.
The small one removes the frame in which the cake is cast
and the large one then lifts the cake and carries it to a car
placed conveniently on the industrial railroad.

The shot-copper well presents no particularly novel
features. There is a launder direct from the furnace, and
the issuing stream of metal is met by an air-blast and a
thin sheet of water which break it up into the desired form ;
the shot falls to the bottom of the well and is caught in an
iron basket which when full is lifted out by a crane and
the shot dumped into a suitable car. Over 8000 Ib. are
handled at a time in the basket.

Silver Building. — In this building, which is of substan-
tial brick construction, the slimes are separated into fine
silver and gold by the sulphuric acid process. The slimes
are trucked in barrels through the tunnel from the base-
ment of the tank-house on to a hydraulic lift which carries
them to the top of one end of the silver building. They
are dumped on an 8-mesh screen, the coarse copper removed,

78 MODERN ELECTROLYTIC COPPER REFINING.

and the slimes washed through to a 6o-mesh screen. The
scrap copper from these screens is returned to the anode
furnaces. The slimes are received in three settlers, which
in turn deliver them to six agitators. The water from the
settlers is siphoned to a settling system outside of the build-
ing. In the agitators, sulphuric acid is added, compressed
air introduced, steam in the heating coils turned on, and
the slimes and solution kept thoroughly agitated by pad-
dles. After settling, the solution being run to the outside
settling system and finally to the sulphate building to be
worked into copper sulphate, the slimes now free from
copper are sluiced into six drying tanks. Up to this point
the slimes have been carried from tank to tank by gravity.
When thoroughly dried by steam coils they are sampled,
weighed, and taken to the furnace-room adjoining. They
now contain from 40% to 50% silver. The slimes are now
charged in water- jacketed cupel furnaces, of which there
are two, each accommodating a charge of from 2000 to 3000
Ibs. The resulting silver slabs are taken to parting kettles
while the slag is melted with lead in a small reverberatory.
The liquor from the parting kettle is carefully siphoned off,
and after settling the entrained gold, it is run into precip-
itating tanks, the cement silver from which is dried in
special ovens and melted into silver bars 990 fine, each
weighing about 1000 oz. The dore bars from the parting
kettles are re -parted in a third kettle and the resulting gold
sediment carefully washed and melted in a small special
furnace into gold bars 985 to 990 fine, weighing about 500
oz. each. All of the furnaces lead into a long flue with a
series of dust-chambers terminating in an 8o-ft. brick
stack. The flue-dust is charged with the slimes into the
cupel furnaces. The acid used is handled here, as else-
where in the works, by compressed air, iron storage tanks
being provided, into which the contents of the acid -tank
cars are siphoned. Compressed air admitted to these

DESCRIPTION AND VIEWS OF REFINING WORKS. 79

tanks forces the acid through a piping system to wherever
required.

Sulphate Building. — The building is of brick and is de-
voted entirely to making copper sulphate. The foul solution
is pumped from the storage well in the tank-house cellar,
by means of steam injectors, to this building, where it is
allowed to trickle through a series of oxidizing tanks con-
taining shot copper, with a corresponding series of settling
tanks interposed. Thus the excess of free acid is neutralized
and the sediment thrown down and separated. The solution
is then boiled to 38° or 40° B. and run into crystallizing
tanks. There are four oxidizing, five settling, three boiling
and 30 crystallizing tanks. The crystallizing tanks are built
over a cellar similar to that of the tank-house, which allows
a, thorough inspection for leaks. At the end of the building
is a washing pan and a revolving conical screen for sizing.
The shaft carrying the screen is hollow and affords a means
of introducing jets of hot air to dry the crystals while they
are being screened. When the mother liquor, which is worked
over several times, becomes so foul that the crystals are
poor, it is sent to a series of iron precipitating tanks outside
the building and the copper content recovered in cement
form.

Blast-furnace Building. — The blast-furnace building, like
the other furnace buildings, is built with a steel skeleton
carrying corrugated-iron sides and roof. The main floor is
at the ground level and is covered with checkered cast-
iron floor plates. The charging floor above is of heavy
planking carried by steel floor beams and is covered with
plate iron around the charging door. The equipment con-
sists of a 33 X 66-in. Fraser & Chalmers water-jacket furnace,
with the usual dust-chambers terminating in an iron stack,
a 30-H.P. shunt motor, a No. 6 A Green rotary blower, a
4Xio-in. Blake crusher, a bucket elevator, and a hydraulic
lift. The material after crushing is carried by the bucket

8o

MODERN ELECTROLYTIC COPPER REFINING.

elevator to a series of bins on the charging floor, near which
are the usual charging scales. The hydraulic lift outside
the building allows material to be trucked, directly when
desired. The slag is dumped on lowlands near the building,
and the pigs of copper are loaded on cars of the industrial
railroad to be taken to the anode furnaces. The flue-dust,
is charged back daily without briquetting. The furnace is
used solely for the reduction of the oxide slag from the
reverberatories. Oyster shells from the adjacent beds and
burnt pyrites from chemical works in the vicinity afford
advantageous sources of the lime and iron needed as flux.

Product. — The output of the works in refined copper is
cast into wire bars, ingots, cakes, and slabs of various stand-
ard sizes as stated below. The quality of the copper is
shown by the following average results, which were obtained
from a number of lots recently tested and analyzed:

Physical Properties.

Composition.

Percentage of Conduc-
tivity. Matthiessen's
St'd. Annealed.

Tensile Strength.
Hard-drawn to No. 1 2
B.&S.

Twists in
6 inches.
Hard-drawn.

Cu.

%

As.

%

Sb.
%

IOO. 1

66,600

43

99-94

O.OO2O

0.0033

This checks closely the figure obtained (100%) for the
average conductivity of all lots produced during a recent
month, the determination of the conductivity of each lot
being part of the daily work of the physical laboratory.

2. Guggenheim Refinery (Perth Amboy Plant).

The Guggenheim electrolytic works, now the Perth
Amboy Plant of the American Smelting and Refining Com-
pany, were built in 1895 at Perth Amboy, N. J., for refining
about 10,000 tons of argentiferous copper annually. These
works were afterwards considerably increased in capacity
and were recently replaced by a well-equipped larger refinery

-

00

I
1

DESCRIPTION AND VIEWS OF REFINING WORKS.

Si

capable of turning out between 100 and 150 tons of elec-
trolytic copper daily, or at least 36,000 tons annually,
while the old refining plant, shown in Fig. 30, has been placed
out of commission.

SIDE VIEW

TOP VIEW

tt-

\ 7 CROSS
\ / SECTION

4t-

FIG. 28. — Shape of Wire Bar with Pointed Ends.
WIRE BARS, POINTED ENDS. (Fio. 28.)

Weight.

Dimensions in Inches.

Pounds.

Length.

Upper Width ,WV

Lower Width, W2.

Depth. D.

77

34*

3t

3

3

100

35

V

3

3iV

135

. 38

3;

3f

155

39

3

3f

3i

175

53

3:

3rV

3i

200

49i

3

3i

3i

225

48

4

3l

4

275

54

41

3l

41

300

51

4'

4i

41

420

84

4

3|

41

575

88

4

4i

Most of the material to be treated is received at the
works in the shape of either pigs of blister copper or anodes.
The very rich gold and silver bearing blister copper from
Aguas Calientes, Mexico, is melted down with low-grade
copper bullion in reverberatory furnaces and partially
refined before it is cast into anodes for the electrolytic
treatment.

The new plant contains 816 depositing tanks and three
520 kw. generators, as against 360 tanks in the old plant
and two 180 kw. generators. Before considering the new
refinery, I will briefly describe the old refinery, with its

MODERN ELECTROLYTIC COPPER REFINING.

SIDE VIEW

TOP VIEW

FIG. 29. — Shape of Wire Bar with Rounded Ends.
WIRE BARS, BLUNT ENDS. (FiG. 29.)

CROSS"
SECTION

Weight.

Dimensions in Inches.

Pounds.

Length.

Upper Width, W).

Lower Width, W2.

Depth, D.

135

37}

3f

Sir

3i

175
212

4<>

-1 5

&

360

6zi

44

4

4*

SQUARE CAKES.
Dimensions in Inches and Corresponding Weights in Pounds.

Th'kness.
Inches.

I*

2

a*

3

3^

4

5

6

Size,
Inches.

14X17
18X18

Pounds.
Ill

Pounds.
I48
2OI

Pounds.
I84
2SI

Pounds.
221
^OI

Pounds.
258

^S2

Pounds.
295
4O2

Pounds.

Pounds.

2OX 2O

254

317

381

44 S

508

615

24.X 24.

466

5^6

62=;

714.

RQ-}

26X 26

K-II

64.4.

752

860

I O7 ^

28X 28

72Q

851

Q72

I 215

I 4.t;8

•^2X^2

077

I I -50

I -7QI

I 628

I Q^^

•^7X^7

i 4.85

I 608

2 122

2 54.6

18X^8

I 6O7

i 8^6

2 2Q5

2755

40X40

1,780

2 O^S

2 54.4.

•7 O52

45X45

2.2S4

2,S?6

3 2OO

3 864.

SLABS.
Dimensions in Inches and Corresponding Weights in Pounds.

Thickness.
Inches.

i*

2

a*

3

3*

4

5

Size,

Inches.

Pounds.

Pounds.

Pounds.

Pounds.

Pounds.

Pounds.

Pounds.

30 X8

114

152

190

228 .

296

304

380

10 X25

118

156

I97

237

277

316

395

12 X22

125

1 66

208

249

29I

332

415

24* X 8

93

124

155

1 86

217

248

310

48 X5i

126

168

210

252

294

336

420

48 X4*

102

136

170

204

238

272

340

DESCRIPTION AND VIEWS OF REFINING WORKS. 83

3o-ton tank-house arid equipment, because of some of its
interesting features.

A. The Old Refining Plant. — The boiler-house contained
five Babcock & Wilcox boilers, rated at 125 H.P. each, and
generating steam at 150 Ibs. pressure, part of which was
utilized for power purposes in the lead refinery.

Two Porter-Allen triple-expansion condensing engines,
running at 250 r. p. m., drove two i8o-kw. General Electric
generators, one of which is shown in Fig. 31. These genera-
tors were of the 8-pole multipolar type, shunt wound, with
smooth core armatures of the ring type, and delivered 1500
amperes at 120 volts.

Good satisfaction was given by woven-wire brushes, of
which there were three to each brush-holder, or twenty-
four in all, the cross-section of each brush being TVXiif
in. The switchboard is shown in Fig. 31.

The cathode or stripping tank system was supplied by
a i2-kw. General Electric generator, shown in Fig. 32,
driven by a standard 25-H.P. Westinghouse engine. It was
a 4-pole machine, with its field separately excited from a
1 10- volt power circuit, and delivered 1,000 amperes at 12
volts. The commutator was 24 inches in length, 14 inches
in diameter, and contained 40 segments, each iyV in. wide.
The brushes, 64 in number, were of carbon, 1.25 in. in
cross-section, and contained a copper-wire core.

In the power-house there were also two 4-pole 4o-kw.
power generators and a 40-kw. no- volt incandescent
lighting generator.

The tank-house contained two groups of tanks: i, those
for refining proper, called the commercial depositing tanks,
and 2, those for making starting sheets or cathodes. -

In the cathode tanks rolled copper plates o.i in. thick
were employed to receive the cathode deposit, which was
permitted to become 0.04 in. thick, both sides of the rolled
copper being thus plated. In former practice wood strips

84 MODERN ELECTROLYTIC COPPER REFINING.

formed a frame about three sides of the plates, but now
grooves filled with insulating material serve the same pur-
pose. The two surfaces of the plates were oiled and covered
with graphite in order to prevent the cathode deposits from
sticking, and the plates were placed in tanks between
ordinary anodes. After the necessary thickness of copper
had been deposited the sheets were stripped from the plates
and were then ready for use as cathodes in the commercial
tanks. There were thirty cathode tanks, each 8 ft. 6 in.
long, 3 ft. deep, and 2 ft. 6 in. wide, supplied with current
by conducting bars 1.25 in. square, placed alongside of each
tank.

A general view of the tanks for the commercial depo-
sition of copper is shown in Fig. 30. They were arranged
in pairs, forming so-called double tanks, as shown in Fig.
33, and grouped in terraces, with a difference in level of
about two inches between each row. The commercial tanks
were constructed of 2 -in. pitch-pine coated with P. & B.
paint, each being 9 ft. 10 in. long, 3 ft. deep, and 2 ft. 6 in.
wide. The electrolyte as prepared for the bath had in solu-
tion, by weight, 16% bluestone and 5% free sulphuric acid.

Each tank contained 22 anodes and 23 cathodes. The
anodes were cast 2 ft. 6 in. long, 2 ft. wide, and 1.25 in.
thick, and had the form shown in Fig. 34.

All of the 360 tanks were placed in series, and the plates
of each tank in multiple. A copper conducting bar 1.75
in. square, afterwards replaced by a bar 1.5 X 3 in. in section,
was supported along the outer edge of each tank, and a
copper strip i in. wide and 0.25 in. thick was placed on top
of the double partition wall between each pair of tanks.
The tops of the cathodes were bent over and hung from
J-in. square copper cross-bars. Fig. 35 illustrates how the
electric current was distributed. It will be seen that the
tanks of each pair are in series the same as the adjacent
pairs of tanks.

DESCRIPTION AND VIEWS OF REFINING WORKS. 85

The anode and cathode plates were separated by about
1.25 in. The current density was about ten amperes per
square foot (counting both sides of the anode plate), and
it required about twenty-four days of twenty-four hours

each to electrolytically transfer tne copper of the 275-lb.
anode to the cathode plate. The voltage, of course, depended
only upon the ohmic resistance of the electrolyte, conduc-
tors, and plates. It averaged between 0.3 and 0.4 volt per

86 MODERN ELECTROLYTIC COPPER REFINING.

tank. With 356 tanks (four tanks were always out of cir-
cuit, having " slime" removed or being repaired) the volt-
meter at the switchboard usually registered from 117 to 120
volts, with a current of 1500 amperes in use.

The deposited plates of pure copper were either sold as
commercial cathodes or they were melted in reverberatories
and cast into wire bars, plates, or ingots.

In the above-described refinery the copper treated was
unusually rich in precious metals, and frequently carried as
much as 300 to 600 ounces of silver and 3 to 4 ounces of gold
to the ton of copper. The rich slimes accumulating in the
bottom of the tanks were carefully gathered and screened
from anode scrap through a perforated sheet copper screen,
which was suspended in a tank in which the slimes were
" boiled," or stirred up with acid so as to expose them to air
as much as possible. The boiling tank was a lead-lined vat
filled with hot dilute sulphuric acid (i of acid to 4 of water)
to a height reaching a little above the bottom of the screen,
and provided with a perforated lead coil communicating
with a Korting injector. The injector supplied both hot
air and steam to oxidize and dissolve the impurities in the
slimes and thus to concentrate the silver and gold during
the boiling.

The slimes constituted at least 4% of the total weight
of the anode copper refined, and after ^screening averaged
15% to 30% of metallic copper, 45% to 50% silver, 0.5%
to i% gold, and from 20% to 35% of impurities, such as.
arsenic, antimony, tellurium, bismuth, and lead, chiefly in
a more or less oxidized condition. Although the boiling was
not continued longer than eighL or nine hours, the greater
parts of the arsenic, antimony, and other impurities were
dissolved and were then removed by siphoning off the
solution and wash water from the silver slimes. The latter
were then dried on iron pans in a hot-air chamber and sent
to the lead refinery.

DESCRIPTION AND VIEWS OF REFINING WORKS. 87

About forty laborers, paid approximately $1.10 per day,
were employed in the copper refinery. A comparatively
large number of men were required because of the need of
washing the anodes. This arose from the fact that the
anodes ran unusually high in silver, and that they had to be
removed from the tanks from time to time, and the adhering
film of silver and other impurities scrubbed off in order to
prevent polarization of the anodes and a reduction of their
effective area.

The refinery occupied a floor space of about 200 feet
square. Under a single roof of several bays it covered the
engine and dynamo plant, the cathode and commercial
tank system, and the crystallizing plant for the recovery
of bluestone.

The cost of the above 30-ton refinery was approximately
as follows:

Building (walls, roof, and trusses) $50,000

Dynamos and fixtures 16,000

Two Porter-Allen engines and one small

Westinghouse engine •. 11,000

Air compressor and pumps 2,000

Lead for lining tanks 12,000

Copper conductors 11,000

Lead burning 2,500

Tanks (woodwork) 10,000

Lumber for floors, etc 2,500

Brick piers for tanks 3,500

Brick paving 1,000

Trolleys ' 2,000

Boiler plant (about 500 H.P.) 15,000

$138,500

The above sum does not include cost of pipes for steam
heating, nor of the tracks for transportation of material.

88 MODERN ELECTROLYTIC COPPER REFINING.

B. The New Copper -Refining Plant. — The new tank-
house of the Perth Amboy plant was erected during
1901 and 1902. From 100 to 150 tons of electrolytic
copper can be refined in it per diem, while the old
tank-house could not treat over 40 or 50 tons daily.
The refinery is at present running at about two-thirds of
its full capacity, the remaining one-third being held in
reserve. This will explain the surplus of generator power
as compared with the actual daily output. The plant
now comprises three 520-kw. generators and 816 depositing
tanks, and produces about 100 tons of electrolytic copper
daily.

The new refinery is said to embody an arrangement,
patented and described by Mr. A. L. Walker, substantially
as follows: The tanks are arranged with their proximate
walls parallel and close together, and are supplied with
current by leading-in and leading-out mains extending to
the end tanks of a given series, these mains being of large
and sufficient cross-section to carry the entire current sup-
plied to all the tanks. Distributing bars of small cross-
sectional area are supported between adjacent tanks, and
the supporting projections of the anodes and of the cathodes
in adjacent tanks rest freely on the same distributing bars,
whereby electrical connection between anodes and cathodes
of adjacent tanks is established through connections indi-
vidually of small and insufficient area to carry the total
current, but collectively of an area sufficient to carry said
current. The supporting projections at one side of the anodes
of the first tank and of the cathodes of the last tank rest
freely on the leading-in and leading-out mains respectively.
With this arrangement heavy conducting bars are entirely
done away with between tanks, and the current is carried
from tank to tank of the series by means of copper bars
having, according to Walker, only 5% of the area of the
large conductors, which are usually 5 sq. in. in cross-sec-

.1 [ -v*^

DESCRIPTION AND VIEWS OF REFINING WORKS. 89

•

tional area, if a 4ooo-ampere current is used. Thus the
Caving in copper by this arrangement, in carrying the cur-
3nt through the series of tanks and including the terminal
conducting bars, is claimed by Walker to be at least 83%
of the best former practice.

In casting anodes, wire bars, and ingots in the above
refinery, four Walker casting machines of very large capac-
ity, as shown in Figs. 36 and 37, are employed, and have
given eminent satisfaction.

Anodes provided with a long and a short lug, as first
used at the Balbach Refinery, are now employed at the
Perth Amboy plant, instead of anodes of the shape illus-
trated in Fig. 34. In Walker's arrangement the lugs of the
anodes in those depositing tanks not connected with the
leading-in mains, which receive the current, rest simply on
the knife edges of small, triangular copper bars, which are
only about 0.5 sq. in. in sectional area, it is reported. It
might seem that the ohmic resistance at the point of con-
tact between lug and this conducting bar would be found
to be very great when such heavy currents as 4500 amperes
are supplied to the tanks with the usual voltage. This is
not the case, however, which is rather remarkable.

The silver slimes collected in the above plant are first
treated with acid, and then dried and sent to the lead re-
finery, where they are added to charges in a lead concen-
trator and enter into the metal cupelled into dore bars,
which are subsequently parted by the Moebius process
electrolytically.

3. The Anaconda Electrolytic Copper Refinery.

The first electrolytic plant at Anaconda, built during
1891 I believe, was altered and enlarged to its present design
and capacity, chiefly under the direction of Mr. Hermann
Thofehrn, in the years 1893-95. The present refinery

9o

MODERN ELECTROLYTIC COPPER REFINING.

covers about 14,000 sq. yd., and consists of two sections,
separated about 100 ft. for security in case of fire. The
boiler-house and the silver mill are located respectively

FIG. 38. — Side View.

FIG. 39.— End View.
Hixon and Dyblie Car and Molds for Casting Anodes Direct from Converters.

200 ft. and 300 ft. distant from the tank-houses. These
buildings, as well as the dynamo-room which adjoins the

-

DESCRIPTION AND VIEWS OF REFINING WORKS. 91

tank-houses, are framed with timber, and covered on their
sides,' gable ends, and roof with corrugated iron. A large
number of fire hydrants, with hose, are distributed through-
out the buildings and are always kept in good working order
by special watchmen. Much of the following detailed descrip-
tion is taken from the Engineering and Mining Journal of
Sept. 19, 1896. I will consider the equipment of the boiler-
house, engine- and dynamo-room, and of the tank-houses
i'n turn, and then describe the actual working of the re-
finery.

The boiler-house contains three sets of two boilers, each
of the Heine pattern, having altogether an evaporating
capacity of 62,000 Ib. of water per hour. Another set of
two boilers of the same capacity serves as a reserve. All
the boilers are connected by a large iron flue which carries
the smoke and gases to a feed-water heater of the Green
pattern, from which they are led to a brick stack 140 ft.
high. The steam and feed- water lines are common to all
the boilers, and the connections are so made as to permit
of connecting or disconnecting any one of the boilers. The
latter are supplied with American Co.'s underfed stokers,
which have given great satisfaction. The ashes are sluiced
to an elevator and finally dumped on the prairie adjoining
the boiler-house. From the cars on a track in front of
the boiler-house, the coal is dumped into large bins, from
which a bucket elevator takes it into the supply bins sus-
pended in front of the boilers. The coal drops from these
bins to the feed-hoppers and is taken by the grates auto-
matically and continuously. The feed-water is handled
by two large Knowles pumps, each of sufficient capacity
to supply all of the boilers alone. The water is taken from
the hot well of the condenser and is delivered by the pumps
through the Green heater to the boilers and acquires in
this way a temperature of about 200° F. Twelve men are
employed in the boiler-house.

92 MODERN ELECTROLYTIC COPPER REFINING.

The engine- and dynamo-room (see Fig. 40) contains,
a Corliss engine of about 800 H.P., a Westinghouse com-
pound engine of 400 H.P., and two triple-expansion engines
of 900 H.P. each. The two last-named engines are directly
•coupled to two dynamos each. This makes a total of
.about 3000 H.P. The Corliss engine runs the dynamos
of the old section of the refinery at present by means of
belting and shafting. The current for the electrolytic
work is supplied by two 220 kw. Westinghouse generators,
belt driven, and five 270 kw. Westinghouse generators,
one of which is belt driven, while the other four are directly
connected to the two triple-expansion engines. This makes
altogether 1790 kw., corresponding to 2560 H.P. Out of
this total, one generator together with the 400 H.P. engine
are kept in reserve, being an electrical unit of 220 kw.,
equivalent to 315 H.P. This reserve unit can be switched
over to any one of six circuits in case of an accident or
repairs to any of the six generators regularly running.
These generators are controlled from a central switch-
board, to which all but two of the conductors lead.

Of the boiler output of 62,200 Ib. of water evaporated
per hour, the two triple-expansion engines, while produc-
ing at the normal rate 1080 kw. or 1544 H.P., consume
at the rate of 15 Ib. per horse-power per hour or 23,160 Ib.
of water. The double Corliss engine, while producing
normally 490 kw., equal to 700 H.P. or 750 H.P. when the
belting losses, etc., are added, consumes at the rate of
30 Ib. of water per horse-power or 22,500 Ib. per hour.
Besides the generators for electrolytic work there are two
dynamos for light and power, one being held in reserve.
These require about 50 H.P., equal to 1500 Ib. of steam.
Then there is a 30-H.P. air-compressor which runs the acid
pumps and consumes about 900 Ib. of steam. The con-
densers for the Corliss and for the triple-expansion ma-
chines take another 1500 Ib. of steam per hour. The

I s

CJ

C o

<! o

DESCRIPTION AND VIEWS OF REFINING WORKS. 93

machinery mentioned in the aggregate consumes a total
of 49,560 Ib. of water, which added to 1500 Ib. required
for heating, makes 51,060 Ib. of water which must be
evaporated in the boilers. This is amply provided for,
as the maximum capacity of the boiler plant, excluding
the reserve boilers, is 62,200 Ib. of water. The total
amount of power consumed corresponds to a maximum
production of 150 tons of electrolytic copper per 24 hours,
or to about 17 J H.P. per ton of copper produced. This
includes the power required for the lifting, the transport-
ing, and handling of the copper, which is done by electric
appliances, the manufacture of the cathodes, the opera-
tion of the silver mill, as well as the production of heat
and light. Labor being more expensive in Anaconda than
power, it is replaced wherever possible by machinery.

The refinery proper (see Fig. 41) is built in two sections,
each tank-house covering a ground space of about 6500 sq.
yd. and containing 600 electrolytic tanks. The tanks are
2.50 m. or about 8 ft. long, 1.50 m. or about 5 ft. 8 in.
wide, and i.oo m. or 3 ft. 3 in. deep. They are built on the
self-insulating plan, that is, they are so constructed as to
allow free access of air to their walls and bottom. A row of
tanks is formed simply by covering a timber framework on
the inside with common planks, and cutting it up into ten
compartments by nine double partitions of the same material,
so as to form a row of ten tanks. Each row is set on its own
foundation, entirely separate from the others, and from the
working floor. A large air-space is left between each
compartment, so that all parts of the tanks, the sides as
well as the bottom, are easily accessible. Every joint in
the woodwork of the tanks and of the foundations is insu-
lated by soaking with insulating material before the tim-
bers and planks are put together. The lead lining of the
tanks is protected by boards against injury from falling
anode scrap. The electric conductors are placed on the

94 MODERN ELECTROLYTIC COPPER REFINING.

sides of the tanks and serve as supports for the electrodes.
The bars are bent in the middle, so as to reach over two
tanks, being positive on one and negative on the other
tank. By means of this bend in the bars all screw con-
nections are avoided between the tanks, and thus only
the different rows require to be connected in the usual
way. This effects an important saving of labor and power,
as it is very difficult to maintain good joints for so heavy
a current in an atmosphere charged with acid and steam,
or moisture. To support the electrodes, flat iron bars are
laid across the tanks and rest on the conductors. Copper
hooks sustain the plates in the liquid and are hooked on
these bars. Ten rows make a set of 100 tanks, and two
sets make a system of 200. Each system fills a bay, and
each bay of the tank-houses is provided with a complete
outfit of machinery, tools, and appliances, making it
entirely independent of the other bays and forming a com-
plete unit by itself. As the composition of the crude
copper changes in regard to its impurities and as the elec-
trolyte has to be altered according to the amount of such
impurities, it is absolutely necessary to be able to sepa-
rate each system from the others. There are six systems
of like capacity of 200 tanks, each being able to turn out
between 25 and 35 tons of electrolytic copper per 24 hours
as a maximum. All the tanks of each system are elec-
trically connected in series and supplied with current pro-
duced by one generator. Each row of 10 tanks has its
individual supply-tank for the circulation of the liquid.
The circulation is established by having the rows built on
an inclined plane. The liquid runs by gravity from one
tank to the next until it reaches the last one, from which
it falls to the collecting tank. The latter conveys the
liquid to the acid pumps, working by air pressure, which
deliver it to the distributor and from there to the small
supply-tanks to begin the same course anew.

DESCRIPTION AND VIEWS OF REFINING WORKS. 9$

The three systems of the old tank-house are provided
with overhead trolleys, one above each double row, by
means of which the tanks are loaded with anodes and the
cathodes are taken away. The full copper charge of a
tank, weighing about four tons, is loaded up or unloaded
in one operation. In the three systems of the new tank-
house each bay has a single electric crane spanning its
whole width, also designed to charge a full tank load at
once. The reason why the first three systems were not
provided with elecric cranes is that the old tank-house was
not suitable for their installation, and the time given for
the construction of the plant was too short to alter the
buildings and to await the construction of the cranes. On
the working floor of the bays runs an electric road of 2o-in.
gauge, by means of which all material is conveyed from
the full-gauge railroad in the buildings to and from the
tanks. The locomotives were designed by Mr. Thofehrn
and built by the General Electric Co. Underneath the
tanks runs another 2o-in. road, which is used to convey
the silver slimes to the silver mill.

Operation of the Refinery. The work in the refinery
is carried out as follows: The men take the anodes from
the railroad cars, transport them by the tank load over
the scales, and place them on a rack. Here the support-
ing bars and hooks are laid over the anodes and the crane
then picks up the charge, conveys it to the tank desired,
lets it down therein, and at the same time places all the
plates in their proper position. In the meantime another
crew of men has placed a load of cathode sheets on a second
rack, hooked on to the supporting bars and ready for use.
These are now taken up by the crane and brought, like
the anodes, to the exact place where they belong. After
this the tank is filled with solution, the electric current
started, and the refining work begun. The circulation of
the solution and the electric current are stopped only in

96 MODERN ELECTROLYTIC COPPER REFINING.

those tanks which are being reloaded and then only for
the time strictly required for this operation. This time,
which includes unloading, cleaning, and reloading, bring-
ing in of fresh material, its preparation, etc., hardly ex-
ceeds one hour for each tank. The unloading of the tanks
goes on in about the same manner as the loading, i.e., the
passage of the electric current and the circulation of the
solution are discontinued, the crane takes out the full
charge of cathode plates, and brings it down to a small,
electrically driven, 2o-in. gauge car, which conveys it to
the railroad for shipment. The remnants of the anodes
in the tanks are then taken out, the silver slimes are re-
moved, and the tanks prepared to be loaded up again. A
current density of 10 to 20 amperes per square foot of
cathode surface is generally employed.

The crude material which the refinery treats is blister cop-
per, containing 98% Cu on an average, and small amounts
of arsenic, antimony, iron, lead, tellurium, selenium, be-
sides about no oz. of silver and J oz. of gold per ton. The
blister copper was formerly, if not at present, cast into
anodes direct from the converters, by employment of the
car and molds shown in Figs. 38 and 39, which are fully
described in U. S. patent No. 539,270 of May 14, 1895,
granted to H. Hixon and J. Dyblie.

The large number of tanks and the high-cost price of
labor at Anaconda necessitated a special means of control-
ling the refining operation. This control was secured by an
automatic register, to which all tanks were connected by
series of five tanks each. A yoke carrying two brushes
slides over the different sections of a commutator-like
device, making one complete turn in an hour, and these
brushes bring into contact the terminals of each series of
five tanks to register the volt meter. In this way all the
tanks are controlled once an hour and the readings regis-
tered on paper automatically. This enables the man in

DESCRIPTION AND yiEWS OF REFINING WORKS. 97

charge to see at a glance the condition of all the tanks in
the refinery. He can see at once if any trouble is in any
one of the tanks; of what nature the trouble is; when it
started and how it developed. He is able, then, to point
out to the foreman the tank in question, and this instru-
ment keeps on recording when the man started to correct
the trouble, how much time it took him to do it, and also
how completely the work was done. The register costs $500
and the wiring about $1000.

The Anaconda Copper Mining Co.'s refinery in 1896
turned out, it is claimed, between 100 and 120 tons of
electrolytic copper daily, and besides sent 80 to 100 tons
of blister copper for refining to Baltimore. Although the
plant was designed to handle 200 tons daily easily in an
emergency, with the use of additional dynamos only, it
has never reached this maximum, and is now producing
at the rate of 84 tons of electrolytic copper daily.

In refining copper in Anaconda we have to consider the
high price of labor, which amounts to nearly $3 on an
average per day per man. The cost of fuel varies between
$2.50 and $7 per ton, according to quality. Sulphuric acid
costs 2.4 cents per pound in Anaconda, and other supplies
are correspondingly high in price. We can safely state that
expenses in Anaconda are generally about twice those at
Eastern industrial centers. The refining work at Anaconda,
according to Thofehrn, costs no less than $14 per ton of
copper produced, including the saving and refining of the
gold and silver slimes.

The total number of men employed in the Anaconda
refinery is 120, inclusive of foreman, assayers, and clerks.
While but 25 men are employed in the newer section of the
refinery for a daily output of 50 tons, the older section
requires about 50 men to refine the same quantity of copper,
as the old tank-house was considered too weak to allow
of the installation of all the modern improvements and

•98 MODERN ELECTROLYTIC COPPER REFINING.

conveniences employed in the newer plant. In actual prac-
tice the combined output of both sections may be put at
100 tons daily, although there is sufficient tankage capacity
for 200 tons, and the latter figure may be reached, accord-
ing to Thofehrn, by simply increasing the electric current.

The electrolytic copper produced at Anaconda averages
98% in conductivity, Matthiesson standard; it has a tensile
strength of 64,000 to 65,000 Ib. per sq. in., can stand 80
twists in 6 in. of No. 12 wire before breaking, and has an
elongation of i^%. All these measurements were taken on
hard-drawn wire.

The anodes delivered to the refinery contain about 2%
impurities, which, during the process of refining, go partly
into the liquid and partly into the slimes. The impurities
which enter the electrolyte are partially taken out on each
turn of the electrolyte through the tanks. A certain amount
of the impurities is allowed to stay in the liquid, however,
while the purification process is regulated so as to limit
the accumulation of these impurities only. The simple
purification process used at Anaconda, necessitating the
use of air and cheap chemicals only, is claimed to be superior
to the old process of crystallizing, which is used in almost
all Eastern refineries in treating impure solutions.

The Anaconda Co. in 1896 produced about 350,000 oz.
of silver in bullion 999 fine and about 1500 oz. of gold as
bullion 950 fine per month from slimes obtained in their
copper refinery. These slimes were sent to the silver mill
in lead-lined tank cars and treated as follows: They were
first hoisted up to screens, washed with water, and all chips
of copper, etc., taken out. The partly cleaned silver mud
was then run out into boiling tanks, where it was freed from
its copper contents, as well as most of its arsenic and anti-
mony, by boiling with acid and steam. After running it
on a filter and thoroughly washing it with water, the mud
was transferred to large cast-iron pans and dried. A con-

DESCRIPTION AND VIEWS OF REFINING WORKS. 99

sequent melting and refining in a reverberatory furnace
reduced it to ingots or plates ready for the parting kettles.
The furnace was charged with about two tons of the dried
silver mud at a time, and after this was melted as rapidly
as a wood fire would permit, it was refined and tapped into
molds which moved on a small train in front of the furnace.
The ingots or plates were then placed in the parting kettles,
in which they were boiled with sulphuric acid. The silver
sulphate obtained was siphoned off, diluted with water and
silver from the solution precipitated on copper plates. The
pure cement silver thus obtained was thoroughly washed,
dried, and melted into ingots in furnace charges of two
tons each. The ingots, weighing about 1200 oz. each, were
assayed, numbered, weighed, and shipped away as bullion,
generally 999 points fine. The gold was allowed to accumu-
late in the parting kettles for a month, when it was taken
out, boiled in acid, washed, dried, and melted down into
ingots, together with suitable fluxes.

The above slime-refining plant or silver mill was re-
modelled later, but the cost of producing fine silver and
gold still remained very high. The slimes are at present
(Sept., 1902) shipped in paper-lined boxes to the Seattle
Smelting & Refining Co.'s works on Puget Sound and sold,
as they can be refined there much cheaper than this could
be done at Anaconda. The actual cost of refining at Seattle
Is not more than i cent per ounce of precious metals in the
slimes. Contracts have been closed, I believe, by which the
Seattle refiner pays for 98% of the silver, all of the gold
at $20 per oz., and the copper in the slimes at the market
price less 6 cents.

4. Nichols Refinery.

The Nichols Chemical Co. is operating electrolytic works
in Brooklyn, N. Y., of an estimated daily capacity of 120
tons of electrolytic copper. There are probably six gener-

ioo MODERN ELECTROLYTIC COPPER REFINING.

ators, each of 75 kw. capacity in the plant, and 120 tanks,
placed in multiple series, with the plates therein arranged
according to the series system. The tanks are 16 ft. long,
5 ft. deep, and 5.5 ft. wide, and built up of i-in. thick and
4-in. wide planking. The anodes are from 0.25 in. to 0.38 in.
thick, 4^ ft. long, and 10 in. wide, and weigh about 65 Ib.
each. They are hammered straight by hand, and are sus-
pended abreast in each tank, 6 anodes forming a row and
about ioo rows filling a tank. As the rows are spaced about
•J in. apart, the drop in potential between any two rows
is probably as low as from o.i to 0.2 volt.

A serious drawback in the series system as applied at
the Nichols Works lies in the much larger quantity of scrap
copper, said to be 25% to 30% of the weight of the anodes,
produced with this process than with the ordinary multiple
system, although it possesses several advantages over the
latter, such as the lower first cost of plant, and the smaller
amount of electrical power required per ton of output.

5. Baltimore Copper Works.

The Baltimore Copper Works, operated by the Balti-
more Smelting & Rolling Co., comprise two refineries,
located at Canton suburb, Baltimore, Md. Their total
output is estimated at about 80 tons and their capacity
ioo tons of electrolytic copper daily. Eleven 80 kw. gen-
erators furnish the required depositing current, which is
supplied to about 540 tanks. The tanks in the smaller
of the two refineries are arranged according to the multiple
system, while those of the larger or Hayden plant are dis-
posed according to the series or Hayden system, fully dis-
cussed heretofore under the caption: "Comparison of
Refining Methods. ' ' In the multiple plant tanks of wood
lined with lead which is itself protected by wooden boards
soaked in paraffin, are used, while in the series system

~

DESCRIPTION AND VIEWS OF REFINING WORKS.

101

tanks of heavy slate coated with tar, which last longer,
but are much more expensive than wooden tanks, are
•employed. The multiple anodes, cast of blister copper 1.25
in. thick, are supported by lugs of phosphor bronze.

Pierce 's semi-mechanical casting apparatus, shown in
Fig. 42, and Walker's casting machines, illustrated in
Figs. 37 and 38, were first applied at these works.

Fig. 43 is a photographic view of the tank-house of the
Hay den plant.

Fig. 44, the interior of the furnace-house, while Figs.
45, 46, 47, 48, and 49 show details of the electrolytic appa-
ratus employed in the Hayden system.

FIG. 45. — Section of Hayden Tank.

FIG. 48. — Section of Siphon.

FIG. 46. — Enlarged Section

showing Anodes with

Deposited Copper.

FIG. 47. — Transverse Section

of Hayden Tank showing

Anodes.

FIG. 49. — Grooved
Slide.

Details of the Electrolytic Apparatus Employed in the Hayden System

The silver slimes obtained as a by-product, after screen-
ing, are treated in lead-lined tanks with dilute sulphuric

102 MODERN ELECTROLYTIC COPPER REFINING.

acid (i part of acid to 4 parts of water) and air drawn in
by a Korting steam injector during three or four hours.
In this short space of time the greater portions of the arsenic,
antimony, copper, and other impurities are dissolved, and
are then removed by siphoning off the solution from the
partly purified slimes. As the slimes contain lead sul-
phate and tellurium, a little bismuth and antimony, and
the gold in a loose form unsuitable for economic parting,
they are melted on a cupel hearth, at first without any flux.
A small quantity of a brownish slag carrying about 20%
of lead and less than 10% of antimony is then skimmed
off, cooled, and picked over, so as to save the larger silver
prills it contains. It is eventually added to molten lead
(scrap, injured tank lining, etc.) in a cupelling furnace.
Here the lead takes up most of the gold and silver in the
slag, and is concentrated until its contents reach about
60% of silver, while a slag is raked off which is poor enough
to be sent to a blast-furnace for reduction of its lead con-
tents.

The second stage of the melting of the slimes consists in
adding about 100 Ib. of niter to the metal bath and skim-
ming off a second slag. This slag is very rich in tellurium,
containing as much as 20%, which could easily.be extracted
from the tellurite of sodium formed, so as to obtain possibly
100 oz. daily if there were any large demand for tellurium.
The silver metal on the cupel now being practically free
from impurities outside of a little copper, is cast into dore
bars to be parted in the usual way.

Finally the copper contained in the dilute acid solution
obtained in removing the arsenic, antimony, etc., from the
impure slimes is precipitated by scrap iron and the pre-
cipitate is melted into impure copper bars, w^hich are sold
or given special treatment.

DESCRIPTION AND VIEWS OF REFINING WORKS. 103

6. Great Falls Refinery.

This plant, belonging to the Boston and Montana Cons.
Copper and Silver Mining Co., now a part of the Amal-
gamated Copper Co., at Great Falls, Montana, produces
approximately 75 tons of electrolytic copper daily. Two
810 kw. generators, turbine driven, furnish the current to
the tank-house, located about 500 yd. distant from the
falls at Black Eagle dam, through huge conductors of cast
copper 8 or 10 in. wide and 2 in. thick.

There are 324 depositing tanks in the refinery, each
containing 20 cathodes and 21 anodes, arranged in multiple
circuit. A current of high amperage (9000 amperes) is
used at Great Falls, because ample and cheap power is
provided. The density of the current is maintained, ac-
cording to report, at from 30 to 40 amperes per square
foot of cathode surface. This seems a dangerously high
density to employ when good deposits are desired, although
it enables the refiner to reduce the time required in turning
out a given weight of cathodes to one-half, or one-third,
of the time usually necessary. Moreover, such high den-
sities are only practicable, it is believed, when the anodes
to be refined are comparatively low in silver and gold, as
at Great Falls, and the solutions are kept comparatively
clear and pure. The tank conductors are about 6 in. wide
and 2 in. thick.

The anodes are cast direct from the large converters
employed in the Boston and Montana smelter, that is, the
anodes- are made from copper poured from ladles filled
from the converters, and not from reverberatory anode
furnaces, as is the usual practice.

J. T. Morrow, the superintendent of the Great Falls
refinery, devised what he deems to be an improved anode,
and invented the following form of mold for casting such

104

MODERN ELECTROLYTIC COPPER REFINING.

anodes. The nature of this invention will best be under-
stood from a description of the -accompanying cuts.

Fig. 50 is a plan view of the mold; Fig. 51 a cross-sec-
tion on the plane 2 2 of Fig. 50; Fig. 52 a detail view show-
ing a portion of the mold and clip-holder in place; Fig. 53
a cross-section of Fig. 52 on the plane 4 4; Fig. 54 an edge
elevation of one of the clip-holders, and Fig. 55 shows
in cross-section, on a plane corresponding to 2 2 of Fig. 50,
the anode and its retaining-clip.

J. T. Morrow's Mold for Casting Anodes.

The anode B, Fig. 55, is of cast metal and provided
with clips C of sheet metal, so formed that the ends D are
cast into the anode and thereby secured. The mold E
for casting the anode is shaped to the form required — such,
for instance, as shown in Fig. 50 — having, preferably, two
lug-forming portions F. The wall K of the mold is much
lower at the points G than at the other points and forms
a low dam, upon which the ends D of the clips C rest, as
seen in section in Fig. 53. A holder-block H is then placed
on each clip and is adapted to fit snugly about the ends D

DESCRIPTION AND VIEWS OF REFINING WORKS. 105

•of the clip and form a continuation of the wall of the mold
above the dam or bridge 6", so as to confine the molten
metal, while allowing the ends of the clips D to project
into the molten metal and be thereby cast into the anode.
Morrow prefers to arrange the holder-block and adjacent
parts in the way shown in the drawings — that is to say, he
provides projecting portions I on the mold E outside the
low wall or dam 6", and fits the weights or holders for the
clips to these projections or extensions L, so that when in
place the downwardly projecting lugs M lie on either side
of the extensions and insure the proper placing of the clip-
holders. The clip-holders are also provided with a down-
wardly extending edge or dam 0, which comes opposite and
registers properly with the dam G, leaving room enough
between for the ends D of the clips C.

In using such a mold and clip-holder the clips are first
laid in position and the holders then placed upon them.
The molten metal is then poured into the mold E and flows
into the lug-forming recess F of the mold. It surrounds
and embeds the ends D of the clips, but is held in check
by the fixed dam G and removable clip-holders//. As
soon as the metal has cooled it is taken from the mold,
with the clips C secured to it, as shown in Fig. 55.

If an anode breaks at or near its slugs during refining,
it is hung upside down from the supporting bar on two
copper-ring hooks passing through holes drilled through
the defective anode. The quantity of scrap copper pro-
duced is thereby reduced.

The following ingenious machine for fastening flat loops
on cathode sheets to secure a better method of their sus-
pension than the method heretofore used was also designed
by J. T. Morrow.

From cathode sheets, which are from -gV to o. i in. thick,
strips about 10 in. long and 3 in. wide are cut, bent at the
middle, and together with the trimmed cathode sheets

io6 MODERN ELECTROLYTIC COPPER REFINING.

fed by hand into the fastening machine. The latter first
slits both the sheets and the loop at one stroke and in a
designated spot in the shape of a cross, and then by means
of a punch laps the double flaps produced by the slitting
process over the cathode sheet, so as to make a secure fas-
tening. The sheets can now be hung in the tanks by simply
passing a copper rod through their two supporting loops.
As the entire face of the cathode is thus made to hang
within the liquid, its active surface is increased, and the
circulation of the electrolyte at its top is not impeded, an
important advantage over the usual method of suspend-
ing cathodes, which consists in bending their entire upper
ends in a roll over the supporting bars.

Circulation of the electrolyte is effected by a terrace
arrangement of the successive tanks, with a difference of
about 2 in. in level between the latter, and the use of large
connecting pipes. There is a complete renewal of the
solution in a tank, say, every three hours. In raising the
electrolyte from the receiving pump, direct-acting plunger
pumps provided with improved rubber bucket lifts are
used, together with * * Monte jus ' ' or pressure tanks of the
usual construction.

The following interesting method of purifying the elec-
trolyte is reported as being used with success at Great
Falls. It consists in treating the solution to be purified
in special tanks and precipitating the impurities, chiefly
arsenic and antimony, together with considerable copper,
more or less loosely on copper cathodes placed opposite
lead anodes, by very strong currents. There are 12 lead-
lined purifying tanks (3 sets of 4 each) to 288 refining tanks,
covered with hoods to carry off escaping fumes. The
cathodes are about o.i in. thick, 30 in. wide, and 36 in.
long, while the anodes are lead sheets of about the same
size sweated on to the copper rods which support the plates.
The precipitated impurities and copper partly hang on the

DESCRIPTION AMD VIEWS OF REFINING WORKS. 107

cathodes and partly drop to the bottom of the vats. These
are cleaned out about every two months and the accumu-
lated arsenical and antimonial mud, carrying from 40% to
60% copper, removed. The mud is finally reduced to im-
pure bars in one of the refining furnaces in the works.

When the cathodes have become thickly incrusted with
impurities or are otherwise rendered useless, they are
melted down into cake copper or into certain brands of
ingot copper, in which a small percentage of arsenic and
antimony is said to be of little consequence, if it is not of
direct advantage in increasing the fusibility of the copper.

The electrolyte purified by the above process is restand-
ardized, returned to the refining tanks, and continued in
regular use until it has become so highly charged with iron
salts, etc., as to interfere with the copper deposition or
cause the depositing copper to blacken. In that case only
is the refinery solution withdrawn from circulation and
pumped to the blue vitriol works, so that the amount of
blue vitriol which it is necessary to handle in the works
is kept down to a minimum.

Although an average of 75 tons of refined copper are
produced daily in the above refinery, it is reported that
only about 20 men, drawing wages of from $2.25 to $2. 75
per diem, are regularly employed in the tank-room.

7. Balbach Refinery.

This electrolytic refinery, operated by the Balbach
Smelting and Refining Co., at Newark, N. J., is the oldest in
the United States. It was started early in the eighties and
is still in active operation, with an output at present of
about 45 tons and a capacity of 50 tons of electrolytic
copper daily, produced with two i25-kw. generators and
one of 3oo-kw. capacity; 430 electro-depositing tanks are
employed.

io8 MODERN ELECTROLYTIC COPPER REFINING.

The Balbach anodes are cast 36 in. long, 24 in. wide,
and i in. thick, each having a long and a short lug, and
weighing from 300 to 400 Ib.

The cathodes are electro-deposited thin sheets of copper,
36 in. long and 24 in. wide, bent over copper suspending
bars, whose bent-up ends rest on the tank walls or con-
ductors.

Twenty anodes and as many cathodes are placed in a
tank. The plates are all in multiple circuit and the tanks
in series. As the tanks are all on the same level, the circu-
lation of the electrolyte is effected by overflow through
I -in. lead pipes to launders placed below the floor level
and feeding in the solution through lead pipes from an
overhead feed launder near the middle of a group of four
tanks, each of the four branches of the vertical feed pipe
supplying a tank with solution.

The tanks are about 9 ft. long, 3 ft. wide, and 4 ft. deep,
constructed of 3-in. plank and lead lined, two tanks being
placed side by side, with one mutual dividing partition,
and two with abutting ends, so that four tanks form a single
group.

All the positive electrodes of a tank are placed in the
same plane with the negative electrodes of the side-ad-
joining tank and vice versa, but the anode lugs of the first
tank are insulated from the cathode bars of the second,
when the cathode bars of the first are electrically connected
to the anode lugs of the second, and vice versa. The con-
nectors are flat pieces of copper used as supports. Light
boards 4 or 5 in. wide are placed over all the connections
so as to protect them from any dripping solution when the
electrodes are lifted out of the tanks. The conductors
are copper bars 4 in. by 0.75 in. in section, each bar being
long enough to extend the length of the two tanks along-
side of which it is placed. The bars are so arranged that
their polarity alternates on the same side of a row of tanks.

DESCRIPTION 4ND VIEWS OF REFINING WORKS. 109

In the latter a current density of 12 to 16 amperes per sq.
ft. of cathode surface is maintained.

At the foot of each double row of tanks are placed two
washing tubs for cleaning the anodes, and running over
each double row are two lines of overhead rails with tackle
for lifting purposes.

The slimes, containing silver, gold, bismuth, sand, etc.,
are cleaned up continuously, and the dore bullion eventually
obtained is parted electrolytically.

When very impure copper is treated, the electrolyte may
carry as much as 7 to 8 g. of arsenic per liter, and yet good
cathodes for wire bars have been produced from anode
material running as high as 5% in arsenic.

Regeneration of the solution is effected by periodically
running off a portion of the electrolyte and replacing it by
fresh solution. The copper, iron, and nickel sulphates are
crystallized out from the portion withdrawn, and the mother
liquor is boiled down so as to obtain arsenic salts, arsenious
acid, etc. If the electrolyte carries much antimony, part
of it precipitates as what appears to be gray antimonious
oxide in the tank discharge launders.

The small quantities of nickel contained in the blister
copper treated, and which concentrate in the acid electro-
lyte, are recovered as nickel salts by repeated fractional
crystallization of the combined salts and a final removal of
the remaining copper by electrolysis. The Balbach Co. was
a pioneer in this method of producing nickel-platers' salts,
for which it has found a ready market ever since 1891.
Under the long and efficient superintendence of Mr. F. A.
Thum and his son, Wm. Thum, it was also the first firm to
introduce and successfully operate the multiple system of
electrolytic copper refining in America, and employ the
appliances and methods now generally used by electrolytic
refiners. An ingenious tilting anode mold, designed by F. A.
Thum, is in use at the Balbach Works. It consists of a

no MODERN ELECTROLYTIC COPPER REFINING.

fixed standard with journals upon which the mold is piv-
oted and may be rotated. The mold itself is made up of
two pieces: the anode mold proper, of the usual form for
casting anodes, provided with a long and a short lug, and a
separate piece with beveled edge, for forming the upper or
head rim of the anode, which piece retains its place as long
as the mold is kept in a horizontal position, and is hinged
to the mold proper. When pouring copper into the mold,
the latter is kept from turning over and discharging its
contents by a clip, which is released as soon as the copper
lias set. The weight of the filled mold then causes it to tilt
over and the head-piece to strike against the standard,
whereupon it reacts in such a way that the weight of the
anode itself forces out the head-piece by wedging against
the beveled edge of the latter and finally allows the anode
to slide from its mold into a truck or conveyor placed ready
to receive it.

8. De Lamar Refining Works.

These works, located near Cartaret, N. J., refine blister
copper from the Bully Hill Mines of California and the
Tacoma Smelting and United States Mining Companies, and
have a capacity for treating 50 tons daily. Current is fur-
nished by one 52o-kw. generator. The number of tanks is
estimated at 408, and their arrangement is probably like
that of the new Perth Amboy refinery of the American
Smelting and Refining Co., as a royalty is being paid by the
De Lamar Works, I understand, to Mr. A. L. Walker for
the use of his patented arrangement of plant. About 10,000
oz. of silver and 200 oz. of gold are obtained daily in treat-
ing the slimes separated from the copper.

DESCRIPTION AND VIEWS OF REFINING WORKS. 1 1 1

... -v

9. The Buffalo Refinery.

This plant forms part of the Buffalo Smelting Works,
located in the Black Rock section of Buffalo, N. Y., and con-
sists of an old and a new refinery.

At the Buffalo Copper Works about 60% of the Calumet
and Hecla Co.'s enormous production of native copper con-
centrates is refined, argentiferous copper material running
at least 15 oz. silver per ton, being melted down and cast
into plates, which are sent to the electrolytic works. Prac-
tically all of the silver in the crude copper passes into the
slimes or tank mud, and is periodically recovered by boiling
the silver mud with sulphuric acid to remove the bulk of
the impurities, refining it on a small furnace hearth and
casting the silver into bars weighing about 1000 oz. each.
The absence of gold from the argentiferous copper obtained
by reducing the native copper ores of Michigan is remark-
able and greatly simplifies the silver-parting process.

The old refinery contains 269 lead-lined tanks, approxi-
mately 10X3X3 ft. in size. Its daily output is 6 tons of
electrolytic copper, with a current measuring about 47 volts
and 600 amperes. A current density of only three amperes
per square foot of the cathode surface is used at Buffalo,
as the management find it advantageous not to push the
refining capacity of the electrolytic plant, especially as the
cost of the power required quadruples with the doubling
of the current density. Each anode plate weighs about
280 lb., and is cast about 1.6 in. thick at top, with three
longitudinal strengthening ribs cast in, as ribbed anodes
were found to hold together better than plain ones. The
starting sheets are formed by deposition on both sides of
copper plates lightly washed, it is said, with a dilute solu-
tion of iodine in naphtha.

The new 40-ton electrolytic copper refinery, built east
of the old works, is furnished with power by a Mclntosh-

H2 MODERN ELECTROLYTIC COPPER REFINING.

Seymour engine, driving a Crocker- Wheeler generator,,
which is guaranteed to deliver a current of 300 volts and
1700 amperes when running at a speed of 126 revolutions
per minute. There are reported to be 490 tanks in the new
refinery, with a basement underneath the tank floor to facili-
tate inspection for leakages and emptying of the tanks. The
circulation of the electrolyte is effected by a cascade
arrangement of the tanks instead of on a level, as in the old
refinery, the solution being pumped to the highest row of
tanks and gravitating downwards. The anodes measure 29 in.
long, 27 in. wide, and about i in. thick, and are provided
with small lugs on top instead of large side lugs, which were
formerly used. Electric traveling cranes and racks similar
to those in use at the Raritan refinery will be used for
charging the tanks with plates and removing the cathodes.

Each heat of refined copper is tested for the mechanical
properties and for the electrical conductivity of the copper
as follows: Representative sample bars weighing about
one pound each are cast at the pouring of every furnace
charge. Pieces of sufficient length from these sample bars
are passed through small rolls and annealed at a dull-red
heat in the muffle of an assay furnace whenever they be-
come too hard. They are then pickled in dilute sulphuric
acid, washed in water and passed through successive dies,
finally being drawn into wire about 0.125 in. in diameter.
These wires are numbered and constitute the samples
used in the Siemens apparatus for making the conductiv-
ity tests. Good annealed copper wire 0.125 in. diameter
should possess a conductivity of at least 98%, should
stand about 55 twists before breaking, and should show a
tensile strength of not less than 24 tons per square inch of
cross-section, according to the usual standard.

The cost of electrolytic refining at the Buffalo works is
reported not to exceed o.3C. per Ib. of crude copper, with
current delivered at a cost of $27 per H.P. per year.

DESCRIPTION AND VIEWS OF REFINING WORKS.

10. Blue Island Refinery.

This electrolytic plant, at Blue Island, 111., is operated
by the Chicago Copper Refining Co. It produces on an aver-
age 5 tons of electrolytic copper per day with two 64-kw.
generators, delivering current to 250 tanks arranged in
series, with plates in multiple.

The circulation of the electrolyte is either effected by
means of two Monte jus or collecting tanks, which are used
alternately, so that as soon as one is full it is automatically
closed, and a small air-compressor forces the solution up
to the distributing tank again, or the circulation is effected
by means of one pressure tank, by using a three-way valve,
working automatically, which increases and relieves the
pressure in this tank every 30 seconds. A circulation of
6 gal. per minute has been found convenient.

The Chicago Copper Refining Co. obtains about 3.75 Ib.
of slimes from every 100 Ib. of anode copper. Formerly the
washed, dried, and screened mud was shipped directly, or
first melted into bars to avoid losses by dusting, and then
sold to lead refiners, but it is now treated so as to recover
dore bars, which are parted, to secure the fine metals, in the
usual way.

B. GREAT BRITAIN.

i. Bottom's Froghall Refining Works.

By JOHN B. C. KERSHAW.

This refinery, at Froghall, Staffordshire, England, and
a smaller electrolytic plant at Widnes, in Lancashire, de-
scribed in subsequent pages, belong to the firm of Messrs.
T. Bolton & Sons, which was established in 1783 and had
existed as a private company until June, 1902, when it
was registered under the joint-stock company laws as
Messrs. T. Bolton & Sons, Ltd., with a capital of $1,440,000.

H4 MODERN ELECTROLYTIC COPPER REFINING.

The combined actual output of the Froghall and Widnes
works for the years 1892 to 1896 was estimated to average
7000 tons per annum. Since the latter year no official
figures are available for publication. It is reported that a
portion of the plant at Froghall is used for depositing nickel
and tin, but no authentic information can be obtained from
the firm on this point.

The electrical power at the Froghall refinery is supplied
by four 275-H.P. triple-expansion engines using steam at
150 Ib. pressure. Each engine drives two dynamos of the
Elwell-Parker type by rope gearing (see Fig. 56), generat-
ing 1500 amperes at 50 volts. The total capacity of this

refinery is, therefore, equal to — • =600 kw.

1000 .

The depositing plant at Froghall is represented by 550
vats, constructed in the usual manner of wood lined with
lead, each measuring 48 in. X3Q in. X42 in. deep. When
fully charged each vat contains 10 anodes and 9 cathodes,
and presents a total depositing surface of 126 sq. ft. The
vats are arranged terrace-wise in order to facilitate circu-
lation, and from 60 to 70 vats are worked in series. The
electrodes in each vat are connected in parallel. Under
normal working conditions 4 Ib. copper are deposited per
hour in each vat, and the maximum output of the Froghall
works, when all the vats are in use, is 700 tons copper per
month, or 8400 tons per year.

The anodes are cast from copper produced at the
Widnes works, and they are allowed to remain in the vats
six weeks. The sludge is worked for silver and gold in the
usual manner.

The electrolytic copper obtained at this refinery is re-
melted, and is then worked up by the firm into wire (at
the Oakamore Wire Works, situated near the Froghall
Refinery), boiler tubes, rolled plate, etc.

If

DESCRIPTION AND VIEWS OF REFINING WORKS. 11$

2. Pembrey Copper Works.

The output of these works, belonging to Elliott 's
Metal Co., Ltd., Burry Port, South Wales, is about 130
tons per week. The number of vats in use is 1065. The
electrodes are arranged according to the multiple process,
which was invented by Mr. James Elkington, one of the
proprietors of the Pembrey works, and was first installed
on a commercial scale there in 1869. Elliott's Co. claims
these were the first works in the world where copper by this
process was produced commercially. A current density
of 10 amperes is employed. Total power generated, 385
kw. ; size of anodes, 10 in. wide by 24 in. long; size of
cathodes, 4 in. wide by 24 in. long; voltage per vat, 0.3 volt.

The electrolyte contains 9 Ib. of bluestone and 4.5 Ib.
of free acid per cubic foot, according to figures kindly
furnished by the manager of the works.

3. Bonn's Widnes Refinery.

The Widnes plant, known as the Mersey Copper Works,
of Messrs. T. Bolton & Sons, Ltd., is used for refining copper
by both the fire and the electrolytic process. A large
portion of the partly refined copper produced at these
works is sent to the Froghall refinery for electrolytic
treatment.

The electrical power for the Widnes depositing plant is
provided by two Galloway engines, which drive by belt-
gearing (see Fig. 57) four 75-kw. generators of the Elwell-
Parker type. When running at 500 revolutions these gen-
erators deposit about 11.5 long tons of copper per 156
hours (Gore).

The vats (see view of interior of tank-house, Fig. 58)
are said to be 4 ft. long, 2 ft. 6 in. wide, and 3 ft. 6 in. deep,
and are placed in rows of 60 tanks in single series, with

u6 MODERN ELECTROLYTIC COPPER REFINING.

gangways between rows. The current passes up one row,
down the next, etc., and is maintained at a density of not
exceeding 10 amperes per square foot of cathode surface.
Each loaded tank contains 10 anodes and 9 cathodes,
placed in parallel circuit.

The anodes consist of auriferous and argentiferous "bot-
toms," obtained by so-called "bottom smelting" of im-
ported argentiferous "regulus" and of refined "coarse"
copper.

In March, 1897, it was stated that Bolton's Widnes
refinery was producing at the rate of 300 tons of electro-
lytic copper per month, although its maximum capacity
under normal conditions is about 350 tons monthly or
4200 tons per annum.

4. Leeds Copper Works.

The following description and views of this plant,
owned by the Leeds Copper Works, Ltd., Leeds, formerly
the English Electro-Metallurgical Co., Ltd., are taken from
an excellent article in Engineering, May 16, 1902, which
is endorsed by the^ operating company.

The works are situated at Hunslet, Leeds, on the site
formerly occupied by the Elmore works, which were erected
to work the Elmore patents for the application of a bur-
nishing tool to copper during the progress of the electro-
lytic deposition, but which did not pay for various rea-
sons, although not, it is claimed, through any inherent
impracticability in the processes.

The present concern has taken up the latter and the
various properties of the old Elmore company, and is now
working them with a large cash capital, and satisfactorily,
it is asserted.

The new works are shown on the plans, Figs. 60 and 61.
They consist chiefly of a boiler and economizer plant, an

I

I

I

I

DESCRIPTION AND VIEWS OF REFINING WORKS.

117

engine- and dynamo-house, buildings containing copper
furnaces, a tank-house or deposit ing-room, and a shop con-
taining draw-benches and other machinery. The Leeds

PRIVATE ROAD TO LEEDS

1

p

.,1; : '•./.,

Draw Benches, etc.

a*

Depositing Shed

2

'

nl " "-"-"-•*
Refiner,
i '.i.j

FIG. 60 — Map of the Leeds Copper Works.

works were built and equipped on the pattern of kindred
works in France, which have been in operation for some
years past at Dives, in Normandy.

The various shops at present cover 17 acres; they are
connected with the Leeds-Liverpool Canal and with the
Midland Railway.

The engine-room is shown in Fig. 62; it measures 215
ft. in length by 65 ft. in width, and contains:

(a) The depositing set of engines, consisting of four
pairs of 250-!!. P. Bollinck cross-compound condensing Cor-
liss engines. The high-pressure cylinder exhausts into a
receiver placed underneath the engine-room; the receiver
supplies the necessary steam to the low-pressure cylinder,
which exhausts into the condenser. Each pair of engines
drives by belt transmission a i7o-kw. Brown-Boveri gen-
erator for depositing.

(6) The power set, formed of three pairs of 400-H.P.

u8

MODERN ELECTROLYTIC COPPER REFINING.

o

I

DESCRIPTION AND VIEWS OF REFINING WORKS. 119

Bollinck cross-compound condensing Corliss engines, similar
in design to the above, each pair of which drives a Brown-
Boveri dynamo of 400-H.P. at 525 volts, and running at
325 revolutions.

(c) The lighting set, which consists of two 300-H.P.
Willans high-speed engines, coupled direct to Elwell-Parker
dynamos.

(d) The main switchboard, in two parts — one for de-
positing and the other for power — and the lighting switch-
board.

The engines are supplied with steam at i4o-lb. pressure
per square inch, from seven Galloway 300 horse-power
boilers, 32 ft. long and 8 ft. 6 in. in diameter, connected to
a chimney 200 ft. high and 10 ft. inside diameter at top.
They are fed by two Worthington feed-pumps. The feed-
water is taken from the canal, but previous to being used
in the boilers, it runs through a pulsometer "torrent"
filter.

The boilers work in conjunction with seven economizers
located in a space between the boiler-house and the engine-
room. All the steam-pipes, valves, and connections are
in duplicate.

The copper used in the depositing process is supplied to
the works in the shape of 96% Chili bars or blister copper;
this is treated, for the removal of arsenic and other impuri-
ties, in three refining furnaces of 12 tons each. The refined
copper is then cast into trough-shaped molds, 13 ft. in
length, for the production of the copper anodes. These are
triangular in section, with slightly concave sides and ver-
tices rounded off. They are cleaned with sulphuric acid
and water previous to being placed in the depositing
tanks.

The depositing department for the production of copper
tubes and for the copper coating of rolls, is illustrated in
Fig. 63. It is located in a building 265 ft. long and 200 ft.

120 MODERN ELECTROLYTIC COPPER REFINING.

wide, which contains 216 acid sulphate-depositing tanks,
in 24 rows of nine tanks placed end to end. Each of the
six bays in the tank-house therefore covers four sets of
nine tanks each, connected in pairs side by side for their
mechanical operation. The plant is capable of a total
weekly output of 75 tons. Two electric motors, one on
each side of the depositing room, alternately drive an under-
ground main shaft, placed underneath the front end of the
tank rows. Link gearing, driven by the main shaft, gives
the rotary motion to the mandrels (cathodes) , around which
the copper tubes are deposited; the same gearing also
causes the backward and forward traveling of the bur-
nisher frame.

For tubes up to 4 in. inside diameter the mandrels are
of brass; for those above 4 in. inside diameter they are
of cast iron, with a brass neck for receiving the current.
The iron mandrels, previous to being used in the acid
sulphate-depositing tanks for the production of copper
tubes, are treated in an alkaline electrolytic bath contain-
ing copper anodes, and coated with a thin covering of cop-
per. The alkaline bath is slightly heated in order to forward
the depositing action. All the mandrels, before being
placed in the acid sulphate-depositing tanks, are carefully
covered with black lead, to facilitate the removal of the
finished tube.

When starting work, the copper anodes are placed in
the tank and the mandrels are nested alongside the former,
but resting at both ends on insulated supports. Acid sul-
phate is then led into the tank by gravity from five cylin-
drical reservoirs on the side of the depositing room ; the
positive current is supplied through suitable lead conductors
to the copper anodes and the negative current is led away
from the mandrels by means of copper conductors and
flexible brushes. The mandrels are caused to revolve,
while agate burnishers, held in wood supports and fitted

DESCRIPTION AND VIEWS OF REFINING WORKS. 121

to a frame placed transversely over the tank, are made to
travel automatically up and down the whole length of the
tubes, as they are being formed by deposition. The frame
travels on paths on the sides of the tank, and is driven,
as above mentioned, by gearing from the main shaft. The
burnishing gives the tubes a uniform density and a per-
fectly smooth surface, it is claimed.

The works can manufacture tubes up to 4 ft. in diam-
eter and 13 ft. in length, though practically there is no
limit to the size. One of the current sizes is 12 ft. by 2^ in.
outside diameter, and about No. 8 wire guage in thick-
ness.

At the end of each operation, and previous to removing
the mandrels with the complete tubes from the tank, a
plug is raised from the latter, and the liquor flows by gravi-
tation to three cisterns built below the floor level of the
depositing room, and in which the sediment, containing
gold and silver, has time to settle. These cisterns have a
capacity of 12,360 cu. ft. The liquor is pumped up from
a third cistern to the large cylindrical reservoirs above
referred to, where it is treated for further use in the deposit-
ing tanks.

The depositing process being carried out with nearly
pure copper, poor in precious metals, the sediment in the
cisterns, which rarely carries as much as 6 oz. of gold to
the ton of residue, is very easily handled.

Four of the bays in the depositing room are provided
with hand-lifting gear ; the manufacture of larger tubes
and the copper coating of heavy rolls are carried out under
the fifth and sixth bays, which are provided with overhead
electric traveling cranes, each of 5 tons capacity.

When the copper-coated mandrels are removed from
the depositing tanks, they are carried to an adjoining
machine-shop and placed in a tube-expanding machine,
in which they are made to revolve under two friction rollers,

J22 MODERN ELECTROLYTIC COPPER REFINING.

which travel along the whole length of the tube. They
are then placed in a power draw-bench and held down.
One end of the mandrel is fastened to a grip, and the latter,
on being hooked to a flat-link chain drawn by a sprocket
wheel, removes the mandrel from the inside of each tube.

This shop contains tube-expanding machines, driven by
belt transmission from an overhead shaft, draw-benches
driven by an underground shaft, and numerous other
tools, such as power-hammers, saws for cutting the tubes
to length, and lathes for turning the mandrels. Overhead
travelers serve all the bays in which heavy work is per-
formed.

Many of the tubes manufactured are drawn in the draw-
benches through dies, in order to give them the required
dimensions to meet certain specifications. This drawing
has the effect of hardening the copper. The tubes are then
placed in a reverberatory furnace, in which they are heated
to a low red heat, after which they are quenched in water
and cleaned in acid and water baths.

The machine-shop contains the required plant for test-
ing the tubes by hydraulic pressure, and for determining
their tensile strength.

Besides the tubes, calico-drying cylinders, calico-print-
ers' rolls, paper-makers' cylinders, seamless copper cylin-
ders for hydraulic machinery, pump liners, and hydraulic
ram covers are produced.

The copper tubes made by this process are claimed to
be able to stand, without showing any defects, the follow-
ing mechanical tests : Doubling close cold and then doubling
over; doubling close cold and opening out; creasing up on
end, expanding, flanging (diameter across the flange being
equal to three times the diameter of the tube) , reducing the
doubled edge of the tube to a knife-edge, and turning back
flat in its hard state, without breaking.

The Leeds Copper Co. is on the Admiralty list for copper

DESCRIPTION AND VIEWS OF REFINING WORKS. 123

tubes and pipes other ttian steam pipes, and the latter are
subject to the British Board of Trade tests.

A plant for the manufacture of drawn brass tubes from
the copper tube scrap, etc., is now being erected at Huns-
let, Leeds. The output of this new plant is intended to
be 25 tons per week.

The Elmore process is also being worked by the Societe
d'Electro-Metallurgie de Dives at Dives in France, and
by the Elmore Metall A. G. at Schladern, near Cologne,
Germany.

5. Vivian Refinery.

This plant forms part of H. H. Vivian & Sons' Copper
Works, it appears, and must not be confused with the
Hafod Copper, Cobalt and Nickel Works, owned by H. H.
Vivian & Co., also of Swansea, Wales. The refinery has
an estimated daily output of 8 to 10 tons of electrolytic
copper.

In the electrolytic process either the whole of the coarse
copper, largely received in the shape of "regulus," is refined
direct, or else auriferous and argentiferous "bottoms" are
produced by fire methods, and these bottoms are then
refined electrolytically. Various makes of generators, El-
more's, Gulcher's, Crompton's and Edison-Hopkinson's,
furnish the required current.

The following are claimed to be characteristic features
of the refining methods adopted: The anodes are cast
shorter and narrower in size than the cathodes, in order to
make the distance, and therefore the electrical resistance
between the edges of adjacent electrodes in the tanks greater
than that between other portions of these plates, and thus
lessen the current density at the edges in comparison and
check the tendency of the copper to "tree" across.

By setting the molds a little out of the level, the anodes
are cast about \ in. thicker at the top than at the bottom,.

124 MODERN ELECTROLYTIC COPPER REFINING.

;so as to check the tendency of the anodes to be eaten away
at or near the surface of the electrolyte and diminish the
production of scrap copper.

In stripping the cathode sheets from their copper pat-
tern plates, the latter are varnished with a weak shellac
varnish containing about i Ib. of shellac to i gal. of alcohol,
which prevents the deposited copper from sticking and at
the same time is not sufficiently thick to insulate the
cathodes from the passage of the current. The edges of the
pattern plates are dipped in " Brunswick black," and the
sheets of copper are then easily detachable from the plates.

The voltages in the tanks are preferably tested with an
ordinary electric bell, especially wound so as to ring at its
ordinary loudness when the tanks are at the correct volt-
age. If the bell rings more or less loudly, it is a sign of
either dirty contacts or of short-circuiting in the particular
tank under test, a method of inspection which appeals more
to the average Welsh workman, it is claimed, than reading
a delicately pivoted and expensive voltmeter.

6. McKechnie's Refinery.

This plant, a part of McKechnie Brothers' Metal Works
at Widnes, produces about 9 tons of electrolytic copper
daily. It is believed to contain 234 depositing tanks and
three dynamos, generating 1500 amperes at 50 volts.

C. GERMANY.
i. Hamburg Refinery.

In 1895 the estimated production of the North German
Refinery at Hamburg was 1728 tons of electrolytic copper
annually or 4.8 tons per diem; at present the output is
probably nearly 10 tons daily. The plant was started in
1876.

DESCRIPTION AND VIEWS OF REFINING WORKS. 125

There are 600 depositing tanks in the above refinery,
each containing a large number of very narrow cast anodes.
Its able manager, Dr. Emil Wohlwill, who formerly had
considerable trouble in his two plants on account of crystal-
line growths on or "sprouting" of his cathodes, has now
succeeded in almost entirely overcoming this difficulty by
interrupting the electrolytic process for half an hour daily
and arranging that the electrolyte contains a small but
sufficient quantity of salt or chloride in addition.

Schnabel gives a table in his " Handbook of Metallurgy, "
p. 266, showing that with each I2-H.P. Gramme dynamo,
delivering a current of 300 amperes at 27 volts tension to
60 tanks, the Hamburg refinery deposits 1984 Ib. of copper
in 24 hours. The effective cathode area of each tank is nearly
162 sq. ft., a current density of 1.85 amperes per sq. ft. is
employed, and about 6.87 Ib. of refined copper are deposited
for each horse-power hour.

It is stated that the anode slimes are reduced in a small
blast-furnace with litharge to a copper-lead alloy, and
that the latter is then cupelled with argentiferous lead.

The Hamburg refinery is certainly the largest electro-
lytic plant in Germany and probably one of the best
arranged.

2. Mansfeld Electrolytic Copper Works.

The product of this plant, operated by the Mansfeld
Kupferschiefer-bauende Gewerkschaft of Eisleben, is esti-
mated at about 5 tons of electrolytic copper daily. In
1886 the approximate production was 734 tons annually
or 2 tons per diem. Wilde's dynamos are employed for
generating the current, which is distributed among the
tanks and electrodes by the ordinary multiple system.

The Mansfeld Copper Co., according to Kershaw, estab-
lished the first electrolytic works outside of England, al-
though Schnabel claims this honor for the Hamburg re-

126 MODERN ELECTROLYTIC COPPER REFINING.

finery, and started their small refinery at Eisleben in 1872,
according to Kershaw, and in 1879, according to Schnabel.
The anodes consist of so-called "bottom copper," rich in
precious metals, obtained from roasted raw matte by the
process of "extra concentration smelting." The latter
process, at the same time, produces a rich slag, which is
retreated, and an extra concentrated matte, which runs
about 78.2% Cu, 0.47% Ag, 0.38% Pb, 0.48% Fe, 0.01%
Mn, 0.27% Zn, 0.35% Ni, 0.06% Co, and 19.68% S,
and is desilverized by the Ziervogel process and refined
like ordinary concentrated matte to a refined copper, con-
taining 99.75 to 99.8% Cu and 8 oz. of silver per ton.
The electrolytic copper produced, being free from silver, is
of a slightly higher grade than this metal and of greater
conductivity.

3. Oker Electrolytic Refinery.

This plant, operated by the Koenigl. u. Herzogl. Com-
munion Huettenamt at Oker, produces about 5 tons of
electrolytic copper daily with water and steam power, rated
at 100 H. P. It was started in 1878. The Oker anodes are
39 in. long, 20 in. wide, and 0.6 in. thick. The cathode pat-
tern plates are made of electrolytic copper less than 0.12 in.
thick, painted over with petroleum spirit and their edges
coated with paraffine.

The cathode-starting sheets are suspended from the con-
ductors by means of copper strips 0.8 in. wide and 0.08 in.
thick, riveted to the sheets and protected where immersed
from the action of the solution by a coating of paraffine.

According to Schnabel, three different types of Siemens
& Halske dynamos are employed at Oker, varying in ten-
sions from 3.5 to 30 volts, according to the number of tanks
to which they furnish current, and in current strengths
from 120 to 1000 amperes. They each deliver an effective
power at the terminals of between 3500 and 4800 watts, and

DESCRIPTION AND VIEWS OF REFINING WORKS. 127

each deposit between 551 and 66 1 Ib. of copper in 24 hours.
The arrangement of electrodes and conductors in a typical

FIG. 64.— Lengths Section of Electrolytic Tank, Oker Refinery.

FIG. 65. — Plan View of Electrolytic Tank, Oker Refinery,
tank is shown in the subjoined cuts, Figs. 64, 65, and 66
(from Schnabel's "Metallurgy).

128

MODERN ELECTROLYTIC COPPER REFINING.

The anode slimes are treated by the so-called rich bullion
smelting process in the blast-furnace, and a product is
obtained consisting of rich lead bullion, matte, and speiss.

FIG. 66. — Cross-section of Electrolytic Tank, Oker Refinery.

This lead bullion is then cupelled and parted in the ordinary
way to recover the precious metals.

4. Goslar Electrolytic Refinery.

This plant, belonging to Borchers Bros., at Goslar, in the
Harz Mountains, produces about i ton of electrolytic copper
daily, it is reported. About 1892 the proprietors of the
above works provided their electrolytic tanks with a novel
apparatus, claimed to have been invented by Werner von
Siemens in 1884 or 1885, for effecting the circulation of the
electrolyte. Within a large lead pipe, b, which is open at
both ends and which connects the center of the bottom of
the electrolytic bath with the surface of the liquid at one
end of the tank, a fine jet of air is blown into the liquid
some distance from the surface of the latter by means of

DESCRIPTION AND VIEWS OF REFINING WORKS.

a glass tube, g. The column of fluid above the lower end of
the glass tube g, mixed with small air bubbles, grows lighter
in sp. g. than the bulk of the liquid in the tank ; it therefore
rises and flows over the upper end of the pipe 6, while at
the lower end of the same pipe a constant current of heavy
liquid rushes in. An almost noiseless but very lively circu-
lation is the result of this process. To prevent waste o£

FIG. 67. — Siemens-Borchers Copper-refining Tank.

liquid by ejecting a lead cover, d, with an opening toward
the electrodes, must be placed over the pipe b. c = collect-
ing tray for anode residues and slimes.

The above apparatus obviates the necessity of having
the electrode flow from one tank to the next of a long series.
The impurities of one tank are not carried through the
whole line. Each bath works independently of the rest.
There should be no occasion for leakage of electric current

I30

MODERN ELECTROLYTIC COPPER REFINING.

and wasteful overflows of liquid, as in the old system. The
electrolyte remains in the bath from the start up to the time
when it must be discarded. The liquid, it is claimed, will
always be found quite clear, a very important point in
hunting up the cause for any troubles in the line. One pipe
line only is required to fill and to empty the tanks by air
pressure and suction. And last, but not least, the current
density may be raised to three or four times that heretofore
used in Europe. This means nothing less than the possibility
of turning out three or four times as much copper as by the
old method; or a given amount of metal will require only
-one-third or one-fourth of the floor space formerly needed.
The economy of operating a refinery with tanks supplied
with the above apparatus, as compared with the old style
of tanks, will appear from the following table furnished by
Siemens & Halske for technical conditions as they exist
in Germany:

Daily Operating Cost with a Production of i Ton
per Diem.

Formerly:
Current Density 3
Amperes per sq. ft.

At Present:
Current Density 10
Amperes persq. ft.

Cost of power ( i horse-power hour @ 5 pfen-

Mark : 1 7 oo

Mark * 30 oo

\Vages

' ' ^o oo

' ' 15 oo

Interest on copper in treatment (5%)
Amortization of the electrical installa-
tion do%)

15.60
" 8 . ^o

4.80
4 IS

'Cost of heating the electrolyte (250 kg.
coal) •

( C

1 ' ^ oo

•Cost of regenerating the solution

' ' 4 oo

Mark: 74.90
= $17.60

Mark: 58.95
= $13-85

5. Schladern Electrolytic Works.

The Elmore Metall-Actiengesellschaft, whose head office
is in London, is operating a modified Elmore process at
Schladern a. d. Sieg, near Cologne, Germany. The process
:and equipment employed being identical, it is claimed,

DESCRIPTION AND VIEWS OF REFINING WORKS. 131

with that of the Leeds Copper Works, excepting in size,
I must refer the reader to the description of the latter
plant on pages 116 to 123 of this monograph. About 1000
H.P. are employed in these works and somewhat better
results have been secured, it is claimed, than in England.

6. Niedermarsberg Refinery.

This refinery, also known as the Stadtberger Huette,
at Niedermarsberg, near Cologne, is operated in connection
with a leaching plant. Carbonate ores containing about
2% Cu are leached with a solution of hydrochloric acid
and salt and with such iron chloride solutions as are ob-
tained in a subsequent stage of the extraction process.
In this way about 1.5% Cu is recovered, while the greater
part of the remaining 0.5% Cu in the ore is extracted from
the dump of the leached ore as follows: The floor of the
dump pile is located on a level above that of the leaching
plant, so that the cupriferous solutions resulting from the
action of the residual chloride solutions in the leached ore,
together with that of the oxygen and moisture of the atmos-
phere on the ore, may be washed down by rain-water into
ditches and their copper contents precipitated therein by
scrap iron. In this way a very high extraction of the copper
contents of the ore is effected and nearly 900 tons of metallic
copper are recovered annually.

The precipitation of the copper is carried out in such a
way as to first throw down practically all of the precious
metals in the solution, together with about 37% of its
copper contents only, thus obtaining a product which is
sent to the electrolytic refinery (arranged on the old Siemens
pattern) for separation, while the greater portion of the
copper in the cupriferous solutions is thrown down by
means of scrap iron free from precious metals, and there-
fore merely requires furnace refining to put it into market-
able shape.

132 MODERN ELECTROLYTIC COPPER REFINING.

The total copper output of the Stadtberger Huette is
nearly 900 tons annually, of which about 330 tons rep-
resents electrolytic copper.

7. Altenau Electrolytic Works.

This plant, operated by the Koenigliches Huettenamt
Altenau im Oberharz, receives power furnished by a Brie-
gleb Hausen turbine, delivering between 17 and 28 H.P.,
according to the available quantity of water. In reserve
is kept a 20 H.P. horizontal condensing engine, working
with 8 atmospheres boiler pressure.

The daily production of electrolytic copper is at present
from 0.8 to i ton.

The anode slimes are mixed with lime, pressed into
.bricks, dried, and smelted in a blast-furnace with a lead
charge and basic slags, and the argentiferous lead bullion
thereby obtained is cupelled and parted in the ordinary
way.

8. Burbach Refinery.

This plant, belonging to Mr. C. Schreiber, of Burbach
Siegen, is a very small one, operated with but 15 H.P. and
producing not over 0.2 ton of electrolytic copper daily by
the ordinary multiple process.

9. Papenburg Electrolytic Works.

These works, belonging to the Allgemeine Elektro-
Metallurgische Gesellschaft, at Papenburg an der Ems, are
said to be producing a small output of copper and nickel,
according to a modified Hoepfner process, using a chloride
solution. It is stated that the capacity for which the works
were designed is as much as i ton of refined copper daily,
although the actual output is only a fraction of a ton, and
that the following process is in use: The ores and matte

DESCRIPTION 4ND VIEWS OF REFINING WORKS. 133

received at the works are leached with a cupric chloride
solution, so as to dissolve their copper, nickel, and silver
contents and simultaneously reduce the cupric salt to the
cuprous state. After purification and being freed from
silver, the solution is passed into electrolytic cells with
carbon anodes and copper cathodes. Chlorine is liberated
at the anodes, and the cupric solution remaining after
electrolysis is withdrawn and reused in leaching a fresh
charge of ore or matte until it is found desirable to recover
the nickel in the solution.

Very recent reports indicate that the Papenburg con-
cern has not achieved as successful results as were ex-
pected, and that the entire plant is therefore being re-
modeled.

D. AUSTRIA-HUNGARY.

By VICTOR ENGELHARDT.
i. Witkowitz Electrolytic Refinery.

This plant, owned by the Bergbau u. Eisenhuettenge-
werkschaft at Witkowitz, Moravia, was started eighteen
years ago in connection with the treatment of pyrites cin-
ders from the acid works, which were then and are now
used in part in making pig iron, owing t6 the difficulty
of obtaining iron ores from other sources low enough in
phosphorus to fall within the Bessemer limit for steel.

The aforesaid pyrites cinders contain, besides a few
tenths of a per cent, of copper, larger proportions of residual
sulphur. Both of these elements are converted into solu-
ble compounds by giving the cinders a chloridizing roast
and then leaching them, whereby a residue is obtained
which is used in making iron. The copper in the leach
liquor is precipitated with iron as cement-copper finally,
which product contains Cu, Fe, Pb, As, Ag, and traces
of Au, and is refined electrolytically. Electrolytic refining

T34 MODERN ELECTROLYTIC COPPER REFINING.

was adopted for the reasons, i, that it enabled the separa-
tion of the copper from the other metals to be effected
easily and completely; 2, because the copper was obtained
as a readily salable product, and 3, because a large differ-
ence in prices existed between electrolytic and fire-refined
copper at the time the works were built.

The cement-copper is first partially refined by a reduc-
ing smelting process and then cast into anodes. The
original cathodes are thin sheets of copper suspended
between anodes in the electrolyte, which contains 35 to
40 g. Cu as copper sulphate and 50 to 55 g. SO3 per liter
of solution.

The composition of the anodes is as follows: 94-98%
Cu, 0.4-1% Ag, 0.2-1% O, 0.02-0.7% Fe, 0.8% As, 0.05%
Pb, and traces of S, Ni, Co, and Au.

At the commencement of operations, in 1884, the plant
contained two rows of 6 tanks each, with 8 anodes and 7
cathodes to a tank. A Siemens machine of 240 amperes
and ii volts furnished the required current, which was
employed at a current density of only 25 amperes per
square meter, equivalent to 2.5 amperes per square foot of
cathode surface.

At present there are 72 tanks in use, the adjoining
tanks of a pair being separated by a partition which allows
free communication of their solutions below. A tank holds
but 4 anodes and 3 cathodes.

The current is furnished by two Siemens & Halske
generators, one cF7 of 240 amperes and n volts, and the
other cH7 of 300 amperes and 17 volts. An average cur-
rent of 290 amperes is used, and a current density of 66
amperes per square meter of surface, i.e., 6.6 amperes per
square foot.

The average annual output of the plant is 92.5 metric
tons of copper, analyzing 99.99% Cu. It is reported that
in one year 2231 metric cwt. of electrolytic copper were

DESCRIPTION AND VIEWS OF REFINING WORKS. 135

produced from 3260 metric cwt. of cement-copper, ob-
tained from 470,600 metric cwt. of pyrites cinders.

2. Brixlegg Electrolytic Refinery.

This plant at Brixlegg, Tyrol, belongs to the K. K. Berg
u. Huettenverwaltung, and contains 60 depositing tanks,
1 2 electrolytic receiving tanks, 6 membrane pumps for
raising the circulating solution, 2 ampere-meters, 3 volt-
meters, 2 torsion-galvanometers, and 2 Siemens & Halske
generators, type cH7, with .air commutators, and delivering
a current of 240 amperes at 20 volts potential.

In 1884 the government installed the first p^ant, con-
sisting of i generator and 2 rows of 10 tanks each,
arranged in cascades, and with a receiving tank and pump
for each row. To this plant additions were made from
time to time, so that at present there are two dynamos
in use, one serving 4 rows of 10 tanks each and the other
2 rows.

The material treated in the electrolytic refinery consists
of gold- and silver-bearing partly refined black copper con-
taining only 90% Cu and i% Ag, besides 0.005% Au.
The electrolyte is an acid solution of bluestone. The
electrolytic cathodes produced are remelted in a refining
furnace and cast into cakes for rolling into sheet, and the
silver slimes are refined by cupellation with lead on a
cupel hearth.

The average annual output of the refinery amounts to
45 to 47.5 metric tons of copper.

E. FRANCE.
i. Dives Electrolytic Works.

These works are operated by the Societe d'Electro-
Metallurgie de Dives, Paris, which is allied to the Leeds
Copper Works, Ltd., and is using a modified Elmore

136 MODERN ELECTROLYTIC COPPER REFINING.

process of depositing copper for tubes, etc., rather than
a refining process proper.

The plant, located at Dives, Normandy, has been run-
ning for some years past and constituted the pattern
after which the Leeds Copper Works have been built and
equipped. The reader is, therefore, referred to the de-
tailed description of that plant on pages 116 to 123.

2. Biache St. Vaast Electrolytic Works.

These works, belonging to the Societe Anonyme des
Fonderies et Laminoirs de Biache St. Vaast (formerly
Eschger, Chesquiere et Cie), with offices in Paris, in 1895
had an estimated output of about 780 tons of electrolytic
copper. The company at present declines to give out any
information.

Dr. C. Schnabel's table, referred to above, shows that
with each 8-H.P. Gramme dynamo, delivering a current of
700 amperes at 4 volts tension to 20 tanks, the Biache
refinery at Pas de Calais deposits nearly 882 Ib. of copper
in 24 hours. The effective cathode area of each tank is a
little over 227 sq. ft., a current density of about 3 amperes
per square foot is employed and about 4.6 Ib. of refined
copper are deposited for each horse-power hour.

The anode slimes are reduced in a blast-furnace with
litharge to a copper-lead alloy, and the latter is then
cupelled with argentiferous lead.

3. Pont de Cheruy Refinery.

This plant, also known as the Grammont Affinerie,
located at Pont de Cheruy, in 1895 had an annual output,
it is claimed, of about 400 tons of electrolytic copper. The
tanks are connected in series and the electrodes in parallel.

The anode residue, containing, say, 25% Cu and i% to
6% Ag, is treated, according to Thofehrn, by exposing it

DESCRIPTION AMD VIEWS OF REFINING WORKS. 137

to the atmosphere and then melting it down to get rid of
the greater part of its metallic oxides other than those of
copper and silver. For this purpose a magnesia brick-lined
refining furnace is used. Finally an alloy containing as
much as 80% Cu and 15% Ag is produced, which is cast
into plates and subjected to electrolysis in special vats, in
which the main refinery current and electrolyte is caused
to circulate. Merchantable copper is thus obtained and
slimes rich enough in silver for final acid treatment in the
usual way.

4. Marseilles Electrolytic Refinery.

This plant, belonging to Hilarion, Roux et Cie, Mar-
seilles, according to Schnabel, in 1898 produced about 551
Ib. of copper daily with a 5-H.P. Gramme dynamo, deliver-
ing 300 amperes at 8 volts tension to 40 tanks. The effect-
ive cathode area of each tank is about 242 sq. ft., the current
density employed about 1.24 amperes per sq. ft., and 4.59
Ibs. of refined copper are deposited per hour for each horse-
power used.

The Societe de Cuivre de France's Refinery at Eguille,
whose annual output in 1895 was reported at noo tons
and whose general arrangement was planned by H. Tho-
fehrn, is not now in operation.

F. RUSSIA.

I. Kalakent Copper Works.

By GUSTAV KOELLB.

These works (owned by the Hon. Carl H. von Siemens
and the heirs of the late Privy Councillor Werner von
Siemens) were established for the purpose of electrolytically
refining crude copper and securing the contained precious
metals, and are located at Kalakent, near the Kedabeg
Copper Works, about 60 wersts or 40 miles southwest of

138

MODERN ELECTROLYTIC COPPER REFINING.

the city of Elisabethpol and 42 wersts or 28 miles from
Dalliar Station on the Transcaucasian Railroad.

Originally the plant was intended to carry out experi-
ments on a large scale for the direct electrolytic extraction
of copper from ores, according to the well-known Siemens,
and Halske sulphate process, but it was remodelled, as far
back as 1889, and operated, at first with 36 tanks, in pro-

10 5 0 30 iO fathoms

FIG. 68.— Ground Plan of Kalakent Works.

ducing merchantable copper from black copper anodes
containing not over 90% Cu, and from which anode re-
sidues, running at most 2 % in silver and gold, were secured.
As the working up of these residues occasioned difficulty,
and moreover, as the obtained electrolytic copper was of
an uncertain quality, this non-paying procedure was given
up, and in its stead the management substituted the
refining of blister copper instead of black copper and
increased the plant in size. As such the works were operated

DESCRIPTION AMD VIEWS OF REFINING WORKS.

139

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140 MODERN ELECTROLYTIC COPPER REFINING.

continuously from 1893 up to 1900, since which time they
have been closed down, because it was believed that no
profit could be realized by them on account of the follow-
ing facts: i. The small percentage of precious metals (on
an average only 0.06%), and of which the gold amounts
to but -fa to -fa part, in the Kedabeg copper; 2, the small
margin of profit between electrolytic and fire-refined copper,
which was reduced to only 25 kopeks per pud, i.e., o.3c.
per Ib. ; and finally, the abnormally high local prices of
certain necessary supplies, such as sulphuric acid, which cost
1.90 rubel per pud, i.e., 2.7C. per Ib. The electrolytic copper-
refining industry in Kalakent is therefore dormant at the
present time.

The Kalakent works embraced 102 electrolytic tanks,
and were designed for an annual output of 25,000 pud, or
450 tons, of fine copper.

Current was obtained from Siemens & Halske shunt-
wound dynamos furnishing 700 amperes at 35 volts, and
of which only one machine was kept in operation at a time.

The tanks were arranged in four rows, all placed on the
same level. The arrangement of the tanks, as indicated
in Figs. 70 and 71, differed from the ordinary and usual
disposition, particularly with respect to the system of
circulating and renewing the electrolyte. It permitted of
making each tank an independent unit, if desired, by the
employment of Siemens air-lifts, two of which were placed
in each tank to circulate the electrolyte. This made pos-
sible the operation of the tanks individually or grouped in
any desired way and number, facilitated the control of each
tank, and permitted the easy renewal or restandardizing
sectionally of impure or abnormal solutions, which is a very
important consideration.

The tanks were built of pine, 2 m. or 6.6 ft. long, 1.15
m. or 3.8 ft. high, and 0.96 m. or 3.1 ft. wide, inside meas-
urements, and were lined with jute linen soaked in asphalt,

DESCRIPTION AND VIEWS OF REFINING WORKS.

141

-Asphalt

142 MODERN ELECTROLYTIC COPPER REFINING.

a method not to be specially recommended, but which was
in this case employed because the price of lead in Russia is
exceptionally high. It possesses this disadvantage, that the
jute lining is apt to be ripped open by falling sharp-edged
pieces of copper, which is, of course, partly provided against
by placing wooden boards on the bottoms of the tanks.
Another difficulty arises from the quality and treatment
of the calking material, in this case Welsh asphalt and
asphalt varnish, for if this material is not boiled sufficiently
long before using, it will be acted upon by the free acid in
the tank and cause an evolution of oxygen and carbonic
acid, which in turn may injuriously oxidize the cathode
copper. Its advantage over lead lining lies only in its
cheapness, and possibly also in the lesser liability therewith
of having short circuits.

The conductors, electrolytic copper bars placed length-
wise of the tanks, were 500 sq. mm. or 1.7 sq. in. in cross-
section, or not quite as large in sectional area as the main
conductors. Each tank contained 15 anodes and 14 cathode
plates, so that it had an anode at each end. The electrodes
were arranged, as usual, in parallel, and the tanks in series
circuit. The electrodes were spaced about 5 to 6 cm. or
about 2 in. apart. It was observed that if this distance
was decreased there arose danger of short-circuiting, and
if increased, the voltage became too great for economy.

The effective anode area per tank was 20 sq. meters
or 200 sq. ft.; of the cathodes, 19 sq. meters or about 190
sq. ft.

Every anode, cast from ordinary blister copper, weighed
between 8 and 10 pud., i.e., about 248 to 360 lb., and
was about 90 cm. or about 3 ft. long, 86 cm. or 2.8 ft.
wide, and 2 cm. to 2.5 cm. or .8 in. to i in. in thick-
ness. Serving as cathodes to receive the commercially de-
posited copper in the tanks were employed sheets of electro-
lytic copper 2 mm. or .08 in. thick, obtained in the usual

DESCRIPTION AND VIEWS OF REFINING WORKS.

143

way in special cathode tanks by electro-deposition on plates
of ordinary rolled copper smeared with oil and graphite,
and whose edges were insulated with paraffine. Before
using they were first freed from adhering oil, etc., by heating,

FIG. 72. — Details of Cathode Connections.

and were then supplied with the necessary suspending and
conducting strips.

To accomplish the circulation of the electrolyte, which
had to be carried on with the greatest energy to secure
good, even copper deposits, each tank was supplied with
two geyser pumps (air-lifts) whose construction is clearly
indicated in Fig. 73. By means of air pressure admitted
through the narrow pipe, shown in the figure, continu-
ously under a pressure of 70 mm. or 2.8 in. mercury column,
the solution from near the bottom of the tank is lifted up
through the larger pipe and overflows into a distributing
trough above the tank to mix with or renew the layer of
electrolyte near the top. In this way about 800 liters of
solution are circulated per tank and hour.

Current densities of 25 amperes up to a maximum of
30 amperes per square meter or 3 amperes per square foot
of cathode area were employed; an increase of the am-
perage above this maximum resulted in brittleness of the
deposited copper unless the acidity of the electrolyte was

144

MODERN ELECTROLYTIC COPPER REFINING.

increased simultaneously. A remarkably high average
current efficiency, 99%, was obtained in the Kalakent
works. In order to secure a very good deposit of fine

FIG. 73. — Circulation Pump (Air-lift).

copper, it was found that the acidity had to be kept at not
less than 70, and generally between 75 and 85 grams of
free sulphuric acid per liter, and that at least 36 grams of
copper had to be present in a liter of solution.

The composition of the better brands of fire-refined

DESCRIPTION AND YIEWS OF REFINING WORKS. 145

blister copper used as Anodes was as follows: 99.57% Cu,
0.06% to 0.08% Ag+Au, 0.027% Pb, 0.038% As, 0.060%
Sb, 0.031% Ni + Co, 0.009% Fe, and traces of bismuth.

Notwithstanding the comparatively low contents in
impurities of the material treated, these accumulated in
the course of time and then necessitated purification of
the electrolyte to prevent deterioration of the copper
deposits. Especially dangerous was the concentration in
the solution of those oxides easily soluble in dilute acid,
such as iron and arsenic (arsenious acid) and also of bis-
muth and antimony compounds. As long as a sufficient
excess of copper over these other metals was present in
the electrolyte, and the total amount of these impurities
did not exceed a certain maximum, indicated by the pecul-
iar appearance of the cathode surfaces, no fault could be
found with the deposited copper. The presence of an
abundance of free sulphuric acid in the bath prevented
the precipitation of the oxides of copper at the negative
poles.

When the impurities in the electrolyte had accumulated
to such an extent as to endanger the quality of the elec-
trolytic copper, the foul solutions were withdrawn from
the individual tanks or tank groups and regenerated, this
regeneration being accomplished with considerable diffi-
culty at first, but finally it was done advantageously as
follows :

The foul solutions were heated and passed over dead-
roasted matte fines heaped in loose-bottomed trays arranged
in series in upright rows. By this method all the sulphuric
acid in the solution, down to about 2 grams per 100 cu. cm.,
was neutralized and combined with copper and iron. The
solution was then allowed to trickle through heaps of
roasted low-grade copper ores, which resulted in the almost
complete neutralization of its acid contents. It was now
diluted with wash waters down to 10° to 12° B. and heated,

146 MODERN ELECTROLYTIC COPPER REFINING.

to free the solution from iron, arsenic, tin, and bismuth,
in lead pans, which were provided with an appliance for
injecting compressed air into the solution. Anode scrap
was suspended in the pans so as to neutralize any remain-
ing portions of acid, and to take up any new acid set free
through separation of iron hydrates, and thereby form
copper sulphate. By blowing compressed air into the
solution heated to about 50° C., the copper in the anode
residues or scrap was quickly dissolved, and the separation
of the iron, arsenic, antimony, tin, and bismuth, which
occurred when the solution had been nearly or completely
neutralized, accomplished. The solution was then con-
centrated up to 14° to 15° B. and clarified in special reser-
voirs. It now contained 3.5 to 4 grams copper per 100
cu. cm., and of impurities only 0.5 to i gram iron, besides
traces of zinc, nickel, and cobalt, and was therefore pure
enough for reuse as electrolyte. The excess of purified elec-
trolyte which gradually accumulated with this method of
regeneration was eventually withdrawn from the circulat-
ing system and worked up into bluest one.

The electrolytic copper put on the market possessed a
purity of at least 99.9% by analysis and averaged 99.93%
copper. It was sold in the shape of plates weighing 8 to 9
pud (i.e. 288 to 324 lb.).

The silver mud or anode slimes obtained as a by-
product in refining the anode copper were not worked up
into gold and silver bullion, but were merely enriched and
shipped to Germany and sold, this being considered a
more profitable procedure than their treatment in Russia.

The enrichment of the slimes, consisting chiefly in the
partial removal of the contained copper, was carried out as
follows :

After removing any adhering solution from the mud by
washing with water and decantation, the slimes were
leached with a quantity of impure acid electrolytic solu-

DESCRIPTION AND VIEWS OF REFINING WORKS. 147

tion, heated to from 50° to 55° C., so as to diminish
their copper contents from 35% or 40% down to 10% or
15% Cu. The leached slimes, which were then sold, aver-
aged 25% to 30% in precious metals, of which gold con-
stituted the fourteenth to seventeenth part. Practically
all of this material was purchased by the North German
Refinery in Hamburg.

2. Nikolajev Refinery.

This electrolytic plant at Nijni Novgorod, comprising
70 depositing tanks, a few years ago was producing at the
rate of 15,000 puds of electrolytic copper per year, which
equals about 0.75 ton per day. A current density of 45
amperes per square meter of cathode surface, equivalent to
4.5 amperes per square foot, is reported as being employed
in refining the crude copper treated.

CHAPTER III.

COST ESTIMATES OF AN AMERICAN COPPER AND NICKEL
REFINERY, WITH GENERAL PLAN AND DETAIL DRAW-
' INGS.

Description and Specifications. — The following preliminary
estimates and plans refer to proposed custom refining works
to be located at Sault Ste. Marie, Michigan, where cheap
water-power is available, and arranged in accordance with
my improved copper-nickel refining process and plant. I
designed the works for a daily productive capacity of 75
tons of fine copper, 7.5 tons of fine nickel, and for refining
the precious metals contained in the material to be treated.

The chief data for the estimates were obtained by se-
curing bids for the items specified, and were carefully com-
piled.

The works are designed especially for treating anodes
of crude nickeliferous copper, averaging, say, 88% Cu,
8.8% Ni, and 22.13 oz. of Ag per ton, valued at approxi-
mately II.SG. and isc. per Ib. for the contained copper
and nickel respectively, and not exceeding 5oc. per oz. for
the contained silver, or a total of about $239.87 per ton.

These nickeliferous copper anodes may be secured by
bessemerizing charges of Sudbury copper-nickel matte added
to common argentiferous copper matte and pouring the
converted metal into the desired shape, or by adding Sud-
bury matte to argentiferous copper concentrates, such as
silver-bearing " mineral" from the Quincy, Isle Royale,
Osceola, and other Upper Peninsula stamp-mills, to bring

148

BALANCE TABL

OFFICE g

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OFFICE

TESTING
ROOU

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SILVER
REFINERY

CRYSTALIZING NICKEL REFINERY AND
HOUSE SEPARATING HOUSE

TANK HOUSE

-

PLAN
FIG. 74. — Plan, Elevation, and Section of

FURNACE BUILDING

Proposed Copper and Nickel Refinery.

[To face page 148.]

SEC!

-647-

PL
FIG. 75. — Plan and Sect on of Proposec

ci Copper and Nickel Refinery.

[To face page 149.]

COST ESTIMATES OF A REFINERY, WITH PLANS, ETC. 149

up the quantity of contained copper to nine or ten times
the quantity of nickel present, refining this charge and
pouring the finished alloy into anodes.

The required power, between 3400 and 4000 H.P., is to
be furnished in the shape of a 3 -phase alternating current
of 10,300 volts, delivered to the high-tension switchboard
of the refinery power-house, at a total yearly cost or price
of $12.50 per metered electrical horse-power at the generat-
ing station.

The works are to be located on a site having facilities
for shipping both by rail and water, flat in topography and
•at, least 12 acres in extent. They are designed with a view
to permitting of future extensions in at least two directions
by a simple duplication of existing sections. Furthermore,
the arrangement shown in the attached plan drawings, Figs.
74 and 75, will permit of erecting a limited section of the
works, with whatever output of refined copper, nickel, and
precious metals may be decided upon at first.

The cost of whatever coal may be used in the remelting
and refining furnaces, in excess of that figured on in the
operating cost of the electrolytic process, is considered as a
•direct charge upon the cost of manufacturing the copper,
nickel, and precious metals into ingots, plates, slabs, and
wire bars. The selling price is assumed at 1 2 ct. per Ib. for
the copper, 24 ct. per Ib. for the nickel, and 50 ct. per oz.
for the silver. In case of any increase or decrease in the
quoted prices of the metals refined, after purchase, the
total profits of refining would, of course, be proportion-
ately increased or decreased.

150 MODERN ELECTROLYTIC COPPER REFINING.

SUMMARY.
Item. Estimated Cost.

Land $1,200

Grading land and building dock 32,000

Tracks 5,040

Office building 13,058

Power-house 68, 100

Tank-house 161,610

Furnace building 143,800

Separating house and nickel refinery. . 34,540

Crystallizing house 20,300

Silver refinery 27,380

Total cost of plant $507,028

Permanent stock on hand 1,296,296

Incidentals, contingencies, and sinking

fund 196,676

Permanent capital invested $2,000,000

Value of total yearly output. $8,046,000

Yearly operating cost $116,280

Price of metal stock purchased

annually 7,625,051

Freight charges to market. . . . 148,600

Total expenses 7,625,051

Total annual profit 420,949

Percentage of profit on capitalization 21.05%

Pitch on all Trusses = 1/g

-Runway Reams 24"

10 Ton Crane

-500

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SOY

spaced 4'OW F">»r U— «*» per 3q.f,.

Steel PurHiis on all Buildings, consisting of 5" I Beams 9%'# and 5"channel

Roof surfaces of Buildings A and E covered with corrugated iron, painted with 3 coats of Graphite Paint.

Sides and Ends of Building E covered with corrugated iron, painted with 3 coats of Graphite Paint, attached

Floors on this building onry.

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Trusses supported on Columns throughout with curtain walls between Columns, exceptin
and prable ends instead of brick curtain walls.

FIG. 76. — Diagram showing General Construction of Proposed Co]

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Side Pressure on E = 30 * per-vejrtica]

Maximum Wheel Loads for Cranes =

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60000* on 2 wheels 9V C. to C.

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which has corrugated iron sidines

nd Nickel Refinery as submitted by the Canadian Bridge Co

[To face page 150.]

r— i

1 1 20" x 05*

16 g''>< 16 S^^-

2ND AND 3RD FLOOR PLAN
[< 3rd Floor

I a

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BOTTOM LATERAL BRACING

ROOF PLAN BOTTOM LATERAL BRACIN

7 7. —Floor and Roof Plan of Buildings for the Proposed Cor

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ind Nickel Refinery. Submitted by the American Bridge Co.

[To face page 151.]

'""T'

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COST ESTIMATES OF A REFINERY, WITH PLANS, ETC. 15*
GENERAL EXPENDITURES.

(1) Lana, 12 acres @ $100 per acre $1,200

( Actual area required, allowing yard room
for doubling the capacity of the plant, 836 X
647 ft.)

(2) Grading land and building dock. 32,000

(Excavations to cost not exceeding $1.00 per
cu. yd., and masonry $6.50 per cu. yd. Dock
to be 400 ft. long by 20 ft. wide.)

(3) Tracks, 168 tons @ $30.00 per ton 5,040

(Industrial road, to be 3o-in. gauge and rails
20 Ib. per yd.)

OFFICE BUILDING.
(50 ft. by 60 ft., two stories.) See Fig. 74.

Foundations $1,850

Brick 4,408

Woodwork i ,200

Furnishings 2,100

Fittings 1,500

Laboratory equipment 2,000

$13,058

POWER-HOUSE.
(50 ft. by 66 ft., one story.) See Figs. 74 and 82.

Foundations $2,000

Brick 4,800-

, Woodwork 1,200

Furnishings 2,100

Fittings 1,500

Switchboards and instruments 5,ooo

Three step-down transformers 12,000

Three rotary converters 39,5oo

$68,100

152 MODERN ELECTROLYTIC COPPER REFINING.

TANK-HOUSE.
(189 ft. by 304 ft., one story.) See Figs. 74, 75, 77, 78, 79, 80, and 81.

Excavations and foundations $7,500

Brick, 240 M. @ $25.00 per M., laid 6,000

Woodwork and furnishings, including 50 windows. 1,000

Fittings, including workbenches and 8 doors 1,000

Steel columns, trusses, and runways 60,000

Roofing, 580 sqs. @ $7.00 per sq 4,060

Pumps and accessories 4,000

Air-compressor 1,700

Lead for lining tanks 21,700

Copper conductors and incidentals 6,000

Lead burning 4,050

Tanks (woodwork) 7,5°°

Lumber for floors and platforms 4,000

Brick foundations for tanks 7,000

Concrete flooring 2,500

Trolleys 2,000

Pipes for steam heating, etc 1,500

Three lo-ton anode-handling cranes 20,100

$161,610

FURNACE BUILDING.

(336 ft. by in ft., one and one-half story.) See Figs. 74, 76, 77. and 82.

foundations $7,500

•Steel columns, trusses, and runways, corrugated

iron roofs and sidings 45,000

One lo-ton traveling crane 3,600

Furnishings and fittings 1,000

:Six 5o-ton reverberating furnaces, with flues,

complete 42,000

One loo-ton blast furnace and accessories 6,000

Six Walker casting-machines, with water-boshes,

complete 2 7 ,000

One Wellman-Seaver charging machine 9,000

'Six 72-foot stacks 2,700

$143,800

ir

^2 Anchor Bolts l"0

CROSS SECTION B-B

-16 0

SIDE ELEVATION

— 160-

SECTION E-E

FIG. 78. — Drawing showing Steel <

HOUSE

t*l on Roof.

" Gables.

Ridge Caps.
* Gutters.

END ELEVATION

Construction of the Tank-house.

[To face page 152.]

/Tx

,

FIG. 79. — Sketch showing

r 3

--

•££

Arrangement of Tanks.

[To face page 153.]

CO57 ESTIMATES OF A REFINERY, WITH PLANS, ETC. 153

154

MODERN ELECTROLYTIC COPPER REFINING.

FIG. 81. — Clearance Sketch of Charging Machine.

SEPARATING-HOUSE AND NICKEL REFINERY.

(128 ft by 50 ft., two stories.) See Figs. 74, 76, 77, 83, 84, 85, and 86

Foundations • $3>7°°

Brick 4,4oo

Woodwork 2,400

Furnishings 2, TOO

Fittings i,5°o

Sixty-eight nickel-depositing tanks and conductors . . 2,720

Steel columns and trusses 9-320

Johns asbestos roofing 680

Two separators 2,000

Two sulphite converters 800

Two concentrators 4°°

Two purifiers 5°°

Two sludge receivers, generators, etc i,oco

Six supply tanks 420

Two large and eight small receiving tanks 800

One air-compressor and receiver 1,100

One electric motor 7°°

$34,540

«- %v) X^i-^^ "? y^yx^ly ^ «iM**ij>fcHj-pM<jiu

filtul

*®®WW$SSQIIW^

CROSS SECTION C-C FURNACE BUILDING

Q

Fici. 82. — Drawing showing Stee. Construction

10 ELEVATION

o

30,000
HGRAM
5TRIC CRANE

SECTION F-F

-30-

Tr

POWER HOUSE

the Furnace Building and Power-house.

[To face page 154.]

SILVER MILL

CROSS SECTION A-A

CRYSTAL

FIG. 86. — Sketch showing Steel Construction of the Silvc

.IZING

SEPARATING HOUSE
END ELEVATION

1 C 6'x 8* *

160

SIDE ELEVATION

cr Mill and the Crystallizing and Separating-house.

160"

SECTION D-D

[To face page 155.]

COST ESTIMATES OF A REFINERY, WITH PLANS, ETC. 155

FIG. 83. — Separating-house. Cross-section.
DESCRIPTION OF APPARATUS.

At separator for precipitating copper sulphide.

B, converter for making copper sulphate.

C, concentrator for removing hydric sulphide.

D, purifier for removing iron and arsenic.

E, sludge receiver.

Ft generator for producing hydric sulphide.

<7, supply tanks for sulphuric acid.

H, receiving tanks for the acid electrolyte.

/, supply tanks for hot water.

/, receiving tanks for copper solution.

K, receiving tanks for nickel solution.

Lt supply tanks for ammonia.

M, air receiver.

JV, tracks.

0, motor for driving machinery.

P, air compressor.

fifl', cross-section of separating-house.

77', longitudinal section.

MODERN ELECTROLYTIC COPPER REFINING.

COS7 ESTIMATES OF A REFINERY, WITH PLANS, ETC. 157

158 MODERN ELECTROLYTIC COPPER REFINING.

CRYSTALLIZING-HOUSE.
(128 ft. by 50 ft., three stories.) See Figs. 74, 76, 77, and 86.

Foundations $3,700-

Brick 2,100

Woodwork ••*•!•( •• 2,400

Furnishings and fittings 1,500

Steel columns and trusses 7,320

Johns asbestos roofing. . !. J .\ . ..; 680

Two oxidizing tanks 200

Two settling tanks 100

Four boiling tanks 600

Twenty crystallizing tanks 1,600

One screen and dryer i oo

$20,300

SILVER REFINERY.
(128 ft. by 50 ft., one story.) See Figs. 74, 76, 77, and 86.

foundations $3, 700

Brick 2,100

Woodwork 2,400

Furnishings and fittings 1,500

Steel columns and trusses, corrugated iron roof.. . 8,000

Electrolytic parting plant 4,000

Three parting kettles and accessories 1,200

One slime-refining furnace 1,200

One silver cupelling furnace 800

Sjix boiling and settling tanks 480

ifryers, screens, tools, etc 2,000

$27,380

COS7 ESTIMATES OF A REFINERY, WITH PLANS, ETC. 159

OPERATING COSTS AND ANTICIPATED PROFITS.

(Based on a daily output of 75 tons of fine copper, 7.5 tons of fine nickel, and
1500 oz. of silver = 85. 227 tons of anodes treated daily.)

Assets.

Plant $507,028

Stock of anodes in treatment, 2557

tons @ $239.87 per ton $613,348

One month's stock on hand of an-
odes, 2557 tons @ $239.87 per
ton 613,348

Copper in conductors, 40 tons @ $250

per ton 10,000

Copper in solution, 200 tons @ $230

per ton 46,000

Nickel in solution, 20 tons @ $680

per ton 13,600

Permanent stock on hand 1,296,296

Incidentals, contingencies, and sinking

fund 196,676

Permanent capital invested $2,000,000

Liabilities.

Cost of refining copper per ton :

Labor $0.75

Current 1.50

Supplies, acid, coal, etc 67

Lighting 08

$3-00
Refining charge 6.00

Profit per ton of copper $3.00

160 MODERN ELECTROLYTIC COPPER REFINING.

Cost of separating and refining nickel per ton:

Labor $0.75

Current 6.00

Supplies, acid, coal, etc. . . 7.17
Lighting 08

$14.00
Royalty, with separating

and refining charge... .200.00

Profit per ton of nickel $186

Yearly Operating Cost :

Copper: 27,000 tons @ $3 $81,000

Nickel: 2,700 tons ©$14 35,280 $116,280

Price of metal stock purchased annually, 30,684

tons @ $239.87 per ton 7,360,171

Freight charges to market, 29,720 tons @ $5

per ton 148,600

Total expenses $7,625,051

Value of Total Yearly Output :

Copper: 27,000 tons @ $240 $6,480,000

Nickel: 2,700 tons @ $480 1,296,000

Silver: 540,000 oz. @ 5oc 270,000

— $8,046,000

Total expenses .Y 7,625,051

Total annual profit $420,949

Percentage of profit on capitalization 21. 05%

APPENDIX.

CHRONOLOGICAL LIST OF PATENTS, BOOKS, AND
SPECIAL ARTICLES ON ELECTROLYTIC COPPER-
REFINING METHODS AND APPARATUS.

1865. Copper Refining, English Pat. No. 2,838 of Nov. 3; James
Elkington.

1869. Copper Refining, English Pat. No. 3,120 of Oct. 27; James

Elkington.

1870. Copper Refining, U. S. Pat. No. 100,131 of Feb. 22; James

Elkington.

1883. "Electrolysis in the Metallurgy of Copper, Lead, Zinc and other

Metals" by C. O. Mailloux. Mineral Resources of the
U. S., Washington, pp. 627-658.

1884. "Data on the Oker Refinery," by H. Froelich. Elektrotechn.

Zeitschrift, p. 466 et seq. Berlin.

1885. 4< Behavior of Constituents of Blister Copper in Electrolytic Re-

fining," by M. Kiliani. Berg- u. Huetten-Zeitg. , p. 249.
Berlin.

Method of Arranging Plates in Copper Refining, U. S. Pat.
No. 322,170 of July 14; Moses G. Farmer, New York.

1886. "Electro-Deposition of Gold, Silver, Copper and other Metals,"

by A. Watt, London.

Refining Process, German Pat. No. 42,243 of Sept. 14; Sie-
mens & Halske.

Method of Using Endless Cathodes in Copper Refining, U. S.
Pat. No. 355,905, Feb. 9; Moses G. Farmer, New York.

ilEinfiuss der Stromdichte auf die Festigkeit des Kathoden-
niederschlags," by H. Hubl Mitth. des K. u. K. militar-
geogr. Instituts, 6, p. 51.

161

1 62 APPENDIX.

1888. Copper Refining, German Pat. No. 53,782 of March i; Carl

Hoepfner.

Copper Refining, U. S. Pat. No. 393,526 of Nov. 27 ; H. Smith.

"Grundriss der Elektrometallurgie," by C. A. Balling, Stutt-
gart, Germany.

1889. Refining Process, German Pat. No. 48,959 of Jan. 3; Siemens

& Halske.

1890. "The Electrolytic Separation of Metals,'' by G. Gore, London.

1891. "The Electro-Deposition of Metals," by G. Gore, London.
"The Art of Electro-Metallurgy," by G. Gore, London.
Copper Refining Apparatus, U. S. Pat. No. 465,525 of Dec. 22 ;

H. Hayden.

1892. "L' Electrolyse," by H. Fontaine. Baudry et Cie, Paris.
"Thofehrn's Electrolytic Refining Process," by H. Fontaine.

The Mineral Industry, Vol. I, p. 163.

"A Treatise on Electro-Metallurgy," by W. G. McMillan, Lon-
don.

Arrangement of Electrodes, U. S. Pats. Nos. 467,350 and
467,484 of Jan. 19; Otto Stalmann.

"Practical Notes on the Electrolytic Refining of Copper" by
Lieut. F. B. Badt. Proc. Am. Inst. Elect. Eng'rs, June 8.
Chicago, 111.

1893. "Thofehrn Process of Purifying Solutions," Berg- u. Huetten-

Zeitg., Bd. LII, p. 53, nach Revue Industrielle fuer 1892,
No. 24 et seq., by Carl Hering.

"American Practice in Electrolytic Copper Refining" by Titus
Ulke. The Mineral Industry, Vol. II, pp. 273-286.

"Thofehrn's Improved Electrolytic Process " by Hippolyte Fon-
taine. The Mineral Industry, Vol. II, p. 282. New York^

1894. "Handbuch der Metallhuettenkunde," Bd. I and II, by Carl

Schnabel. Springer, Berlin.
"Zur Elektrolytischen Gewinnung von Kupfer nach dem

Hoepfnerschen Verfahren," by E. Jensch. Chem. Zeitg.,

p. 1906. Berlin.
"Progress in Electrolytic Refining of Copper during 1893," ^7

T. Ulke. The Mineral Industry, Vol. III. New York.
Arrangement of Electrodes, U. S. Pat. No. 514,275 of Feb. 6;.

T. Randolph.

1895. ('Data on the Marches^ Process at Stolberg," by E. Cohen.

Zts. Elektrochemie, Jahrg. II, S. 25.

"Progress in Electrolytic Refining of Copper during 1894," by
T. Ulke. The Mineral Industry, Vol. IV, New York.

APPENDIX. 163

1895. Car and Set of Molds for Casting Anodes Direct from Con-

verters, U. S. Pat. No. 539,270, May 14; H. Hixon and
J. A. Dyblie.

"The Electrolytic Refining of Copper," by M. Barnett. Peters'
Modern Copper Smelting, pp. 576-606. New York.

1896. "Elektro-Metallurgie," by W. Borchers. Braunschweig, pp.

166-217.
"The Progress of Electrochemistry and Electrometallurgy in

1895," by W. Borchers. The Mineral Industry, Vol. IV,

pp. 806-808.
"Improvements in the Electrolytic Refining of Copper" by T.

Ulke. Engineering and Mining Journal, Nov. 14. New

York.
Apparatus for Electrolytic Circulation, U. S. Pat. No. 563,093

of June 30; A. E. Schneider and Oscar Szontagh.
"Present Method of Treating Slimes from the Copper Refineries"

by T. Ulke. The Engineering and Mining Journal, Nov. 28.
"The Anaconda Refinery" The Engineering and Mining Jour-
nal, Sept. 19, pp. 271-273. New York.
"Progress in the Electrolytic Refining of Copper " by T. Ulke.

The Mineral Industry, Vol. V, p. 89. New York.

1897. "Electric Smelting and Refining" by W. Borchers and Walter

G. McMillan. London.

"Copper Refining" by J. B. C. Kershaw. The Electrician,
London, Jan. 8, pp., 337, 338.

"Tank Residues in Electrolytic Copper Refineries" by Ed-
ward Keller. Journal Am. Chem. Soc., XIX, No. 10.

"Copper Refining" by John B. C. Kershaw. The Electrician,
Jan. 1 8, pp. 385, 386. London.

"Electric Copper Refining in the United States" by T. Ulke.
Cassier's Magazine, Sept. New York.

1898. "Progress in Electrolytic Copper Refining in 1897," by T.

Ulke. The Mineral Industry. Vol. VI, pp. 238-244. New

York.
"Handbook of Metallurgy" by Carl Schnabel. Translated by

Henry Louis, London. Vol. I, pp. 260-274.
"Die Verarbeitung des Elektrolyten in Amerikanischen Kupfer-

werken" by T. Ulke. Zts. f. Elektrochemie, 4, 309.

1899. Method of Producing Electrolytic Copper Wirebars, U. S. Pat.

No. 638,917 of Dec. 12; Elisha Emerson, Providence, R.I.
Method of Electrolytically Refining Copper, U. S. Pat. No.
617,886; Elisha A. Smith, Anaconda, Mont.

1 64 APPENDIX.

1899. "The Electrolysis and Refining of Copper," by Edward Keller.

The Mineral Industry, Vol. VII, pp. 229-260. New York.

"Einfiuss der Temper atur des Elektrolyten in der Kupf err agina-
tion" by Foerster and Seidel. Zts. f. Elektrochemie, 5, 508.

Mold for Casting Anodes, U. S. Pat. No. 631,471 of Aug. 22;
J. T. Morrow, Great Falls, Mont.

1900. "Treatment of Silver Slimes in Electrolytic Copper Refining"

by J. C. Roberts. Colorado School of Mines Quarterly for
May. Golden, Col.

"Progress in the Electrolytic Refining of Copper during 1899,"
by T. Ulke. The Mineral Industry, Vol. VIII, pp. 184-
188, New York.

1901. "The Present Status of the Electrolytic Refining Industry in the

United States," by T. Ulke. Electrical Review, Jan. 12,

p. 85. New York.
Plant for the Electrodeposition of Metals, U. S. Pat.- No.

687,800 of Dec. 3; Arthur L. Walker, Perth Amboy, N. J.
"The Raritan Copper Works" by Lawrence Addicks. The

Mineral Industry, Vol. IX, pp. 261-276. New York.
"Progress in the Electrolytic Refining of Argentiferous Copper,"

by T. Ulke. The Mineral Industry, Vol. IX, pp. 223-234.

New York.
Rapidly Rotating Mandrels, British Pat. No. 9,731; S. O.

Cowper-Coles.
Improved Form of Cathode Plate, U. S. Pat. No. 683,263 of

Oct. 12 ; E. G. Elliott and V. Kishner, Perth Amboy, N. J.
Improved Form of Cathode Plate, U. S. Pat. No. 684,291 ; W.

A. McCoy, Perth Amboy, N. J.

1902. Metallurgical Crane, U. S. Pat. No. 697,788 of April 15 ; David

W. Blair.
"Electrolytic Process of Recovering Copper," by N. S. Keith.

Electrical Review, Vol. 40, No. 12, of March 22. New York.
Art of Refining Composite Metals, U. S. Pat. No. 694,699 of

March 4; T. Ulke, Sault Ste. Marie, Ont.
"Progress in the Electrolytic Refining of Copper in 1901," by

T. Ulke. The Mineral Industry, Vol. X, pp. 217-228.

New York.
1 Treatment of Slimes from the Electrolytic Refining of Copper"

by Robert L. Whitehead. The Mineral Industry, Vol. X,

pp. 229-230. New York.
"Corrosion in Depositing Copper" by H. Sayer and F. S. Spiers.

Electrochemist and Metallurgist, April, p. 103. London.

APPENDIX. 165

1902. "Progress in the Making of Elite Vitriol," by O. Hofmann. The

Mineral Industry, Vol. X, pp. 231-242. New York.
"Electrochemical Polarization," by C. J. Reed. Journal of the

Franklin Institute, April. Philadelphia, Pa.
"Elektro-Metallurgie," 3. Auflage, by W. Borchers, pp. 182-

268 incl. Braunschweig, Germany.
"Electro-Plating and Electro-Refining of Metals," by Arnold

Philip. Being a revision of Watt's " Electro-Deposition."

London.
"The Electrolytic Dissolution of Soluble Metallic Anodes, "by

Woolsey McA. Johnson. Trans. Am. Electrochem. Soc.t

Vol. II, pp. 171-173. Philadelphia.

INDEX.

PAGE

Altenau Electrolytic Works 132

American Electrolytic Copper Refinery, Design of 148-160

Cost Estimates of 150-160

Crystallizing House, Cost of 158

Description and Specifications 148

Furnace Building, Cost of 152

General Expenditures 151

Office Building, Cost of 151

Operating Costs and Profit , 159

Operating, Estimate of Costs of 150

Plant, Estimate of Costs of. ... « 150

Power House, Cost of , 15 1

Separating House and Nickel Refinery, Cost of. 154

Silver Refinery, Cost of 158

Stock, Estimate of Costs of. 150

Tank House, Cost of 152

Anaconda Electrolytic Copper Refinery 89-99

Anodes, Casting of 76, 77, 89, 96, 101

Anodes, Molds for Casting of. 104, 109

Anodes, Shapes of 85 , 101, 104

Assaying of Copper Material 16

Balbach Refinery 107-1 10

Baltimore Copper Works 100-102

Biache Refinery 136

Blast-furnace Building, Raritan Works 79

Blue Island Refinery 113

Bluestone, Making of. 24-46

Bolton's Froghall Refining Works 113, 114

Bolton's Widnes Refinery 115

Books on Electrolytic Copper Refining 161-165

167

1 68 INDEX.

PAGE

Brixlegg Refinery 135

Buffalo Refinery in, 112

Burbach Refinery 132

Casting Machines 89, 90, 101

Chemistry and Physics of Refining 17-26

Chronological List of Literature on Refining 161-165

Comparison of Methods 7-13

Copper, Testing of 60, 61, 112

Cost Estimates of Typical American Refinery 148-160

Cost of a 30-ton Refinery 87

Cost of Producing Electrolytic Copper 3

Data, Historical I

Data, Statistical $2-55

Definitions and General Principles 3-6

De Lamar Refining Works no

Descriptions of Refining Works 56-147

Detail Drawings of Typical Refinery I53~I57

Development of Electrolytic Copper Refining 1,2

Dives Electrolytic Works : 135

Efficiency of Plants 14

Electrolytic Copper, Cost of Producing 3

Electrolytic Copper Refineries, Descriptions of 56-147

Electrolytic Copper Refineries, Outputs of. 52

Electrolytic Copper Refineries, Plans and Views of 58-101

Electrolytic Copper Refining, Development of. I, 2

Electrolytic Copper Refining, Literature of. 161-165

Electrolytic Copper Refining, Methods and Apparatus of 7~5*

Froghall Refinery :•••*» •• XI3

Furnace Building, Cost of. 152

General Expenditures for Grading Land, etc 151

General Expenditures for Land, Tracks, etc 15 r

General Plans of Typical American Refinery 148-152

Goslar Refinery 128

Great Falls Refinery 103-106

Guggenheim Refinery 80-88

Hamburg Refinery •••;•, I2

Hayden System, Discussion of . . . . I7~3> 100-102

Historical Data I, 2

INDEX. 169

Kalakent Copper Works 13?

Leeds Copper Works 116-122

List of Patents, Books and Special Articles 161-165

Making Bluestone 27-46

Mansfeld Copper Works 125

Marseilles Electrolytic Works 137

McKechnie's Refinery 124

Metal Stock Required in Refining 14, 15

Methods, Comparison of 7-!3

Modern Practice, Resume of 51

Multiple System, Discussion of 7-13

Nichols Refinery 99

Nickel Refinery, Cost of 154

Niedermarsberg Refinery 131

Nikolajev Refinery 147

Office Building, Cost of 151

Oker Refinery 126

Operating Costs and Profits 159

Outputs of Electrolytic Works 52~55

Papenburg Electrolytic Works 132

Patents, List of. 161-165

Pembrey Copper Works 1 15

Perth Amboy Plant 80-88

Pont de Cheruy Refinery 136

Power House, Cost of 15 1

Raritan Copper Works 56

Refining, Chemistry and Physics of 17-26

Refining Methods 7-I3

Refining, Stock of Metal Required in 14

Refining Works, Descriptions and Views of 56-147

Resum£ of Modern Practice 5X

Sampling and Assaying 16

Schladern Electrolytic Works 130

Separating House, Cost of 154

Series System, Discussion of 7-13, 99-102

Shapes of Wire Bars Cakes and Slabs 8l, 82

Silver Refinery, Cost of 158

Slimes, Treatment of. 47~5O

i 70 INDEX.

PAGK

Special Articles on Refining 161-165

Stock of Metal in Refining 14

Sulphate Building, Raritan Works 79

Tables giving Outputs, etc., of Copper Refineries 52~55

Tank House, Cost of 152

Tank House, Plans and Details of 148-153

Treatment of Slimes 47~5°

Treatment of Solutions 27-46

Vivian Refinery 123

Walker's Casting Machine loo

Witkowitz Refinery 133

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Merriman and Brooks's Handbook for Surveyors 16mo, mor., 2 00

Merriman's Elements of Sanitary Engineering Svo, 2 00

Nugent's Plane Surveying Svo, 3 50

Ogden's Sewer Design 12mo, 2 00

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Siebert and Biggin's Modern Stone-cutting and Masonry. . . .Svo, 1 60

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Bchuyler's Reservoirs for Irrigation, Water-power, and Domestic

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" Elements of Analytics . 3chanics 8vo, 3 00

MATERIALS OF ENGINEERING.

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" Inspection of the Materials and Workmanship Em-
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Church's Mechanics of Engineering 8vo, 6 00

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Keep's Cast Iron 8vo, 2 *•

Lanza's Applied Mechanics 8vo, 7 M

Martens's Handbook on Testing Materials. (Henning.).2 v., 8vo, 7 60

Merrill's Stones for Building and Decoration 8vo, 6 00

Merriman's Text-book on the Mechanics of Materials 8vo, 4 09

Merriman's Strength of Materials 12mo, 1 00

Metcalf s Steel. A Manual for Steel-users 12mo, 2 00

Patton's Practical Treatise on Foundations 8vo, 6 00

Rockwell's Roads and Pavements in France 12rao, 1 26

Smith's Wire: Its Use and Manufacture Small 4to, 3 00

" Materials of Machines. . 12mol 1 00

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Spalding's Hydraulic Cement 12mo, 2 00

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Thurston's Materials of Engineering 3 Parts, 8vo, 8 00

Part I. — Non-metallic Materials of Engineering and Metal-
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Tillson's Street Pavements and Paving Materials 8vo, 4 00

Waddell's De Pontibus. (A Pocket-book for Bridge Engineers.)

16mo, morocco, 3 00

Specifications for Steel Bridges 12mo, 1 20

Wood's Treatise on the Resistance of Materials, and an Ap-
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* Elements of Analytical Mechanics 8vo, 3 00

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RAILWAY ENGINEERING.

Aadrews's Handbook for Street Railway Engineers. 3x5 in mor., 1 25

Jerg'a Buildings and Structures of American Railroads.. .4to, 6 00

Brooks's Handbook of Street Railroad Location.. 16mo, morocco, 1 60

Butts'g Civil Engineer's Field-book 16mo, morocco, 2 60

Crandall's Transition Curve 16mo, morocco, 1 66

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Dawson's Electric Railways and Tramways. Small 4to, half mor., 12 60
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Dredge's History of the Pennsylvania Railroad: (1879.) .Paper, 6 00

* Drinker's Tunneling, Explosive Compounds, and Rock Drills.

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Usher's Table of Cubic Yards Cardboard, 26

Godwin's Railroad Engineers' Field-book and Explorers' Guide.

16mo, morocco, 2 60

Howard's Transition Curve Field-book 16mo, morocco, 1 60

Hudson's Tables for Calculating the Cubic Contents of Exca-
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Molitor and Beard's Manual for Resident Engineers 16mo, 1 00

.Nagle's Field Manual for Railroad Engineers. . . . 16mo, morocco, 3 00

Fhfibrick's Field Manual for Engineers 16mo, morocco, 3 00

Pratt and Alden's Street-railway Road-bed 8vo, 2 00

Beerles's Field Engineering 16mo, morocco, 3 00

" Railroad Spiral 16mo, morocco, 1 60

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DRAWING.

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Coolidge's Manual of Drawing 8vo, paper, 1 00

Durley 's Kinematics of Machines 8vo, 4 00

Hill's Text-book on Shades and Shadows, and Perspective. . 8vo, 2 00
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MacCord's Elements of Descriptive Geometry 8vo, 3 00

Kinematics ; or, Practical Mechanism 8vo, 6 00

Mechanical Drawing 4to, 4 00

Velocity Diagrams 8vo, 1 60

• Mahan's Descriptive Geometry and Stone-cutting 8vo, 1 60

Mahan's Industrial Drawing. (Thompson.) 8vo, 3 60

Reed's Topographical Drawing and Sketching 4to, 5 00

Reid's Course in Mechanical Drawing 8vo, 2 00

" Text-book of Mechanical Drawing and Elementary Ma-
chine Design 8vo, 3 00

Robinson's Principles of Mechanism 8vo, 3 00

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Warren's Elements of Plane and Solid Free-hand Geometrical

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Manual of Elementary Projection Drawing. .. .12mo, 1 60
Manual of Elementary Problems in the Linear Per-
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Primary Geometry 12mo, 76

Elements of Descriptive Geometry, Shadows, and Per-
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Elements of Machine Construction and Drawing. .8vo, 7 50
Problems, Theorems, and Examples in Descriptive

Geometry 8vo, 2 60

Weisbach's Kinematics and the Power of Transmission. (Herr-
mann and Klein.) 8vo, 6 00

Whelpley's Practical Instruction in the Art of Letter En-
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Wilson's Topographic Surveying 8vo, 3 60

Wilson's Free-hand Perspective 8vo, 2 59

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ELECTRICITY AND PHYSICS.

Anthony and Brackett's Text-book of Physics. (Magie.)

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ments 12mo, 1 00

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Classen's Qantitative Chemical Analysis by Electrolysis. Her-

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Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 00

Dawson's Electric Railways and Tramways.. Small 4to, half mor., 12 60
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16mo, morocco, 4 00

Flather's Dynamometers, and the Measurement of Power. . 12mo, 3 00

Gilbert's De Magnete. (Mottelay.) 8vo, 2 60

Holman's Precision of Measurements 8vo, 2 00

Telescopic Mirror-scale Method, Adjustments, and

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Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00

Le Chatelier's High-temperature Measurements. (Boudouard —

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LOb's Electrolysis and Electrosynthesis of Organic Compounds.

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Lyons'* Treatise on Electromagnetic Phenomena 8vo, 0 00

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* Tillman. Elementary Lessons in Heat 8vo, 1 60

Tory and Pitcher. Manual of Laboratory Physics. .Small 8vo, 2 00

9

LAW.

* Davis. Elements of Law 8vo, 2 60

* " Treatise on the Military Law of United States. .8vo, 7 00

Sheep, 7 50

Manual for Courts-martial 16mo, morocco, 1 50

Wait's Engineering and Architectural Jurisprudence 8vo, 6 00

Sheep, 6 59

Law of Operations Preliminary to Construction in En-
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Winthrop's Abridgment of Military Law 12mo, 256

MANUFACTURES.

Beaumont's Woollen and Worsted Cloth Manufacture. .. .12mo, 1 50
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Holland's Iron Founder 12mo, cloth, 2 60

" The Iron Founder " Supplement 12mo, 2 50

Encyclopedia of Founding and Dictionary of Foundry

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Eissler's Modern High Explosives 8vo, 4 00

Effront's Enzymes and their Applications. (Prescott.).. .8vo, 3 00

Fitzgerald's Boston Machinist 18mo, 1 00

Ford's Boiler Making for Boiler Makers 18mo, 1 00

Hopkins's Oil-chemists' Handbook 8vo, 3 00

Keep's Cast Iron 8vo 2 50

Leach's The Inspection and Analysis of Food with Special
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Metcalf's Steel. A Manual for Steel-users 12mo, 2 00

Metcalfs Cost of Manufactures — And the Administration of

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Meyer's Modern Locomotive Construction 4to, 10 00

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Smith's Press-working of Metals 8vo, 3 00

" Wire: Its Use and Manufacture Small 4to, 3 00

Spalding's Hydraulic Cement 12mo, 2 00

Spencer's Handbook for Chemists of Beet-sugar Houses.

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Thurston's Manual of Steam-boilers, their Designs, Construc-
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* Walke's Lectures on Explosives 8vo, 4 00

West's American Foundry Practice 12mo, 2 60

" Moulder's Text-book 12mo, 2 60

Wiechmann's Sugar Analysis Small 8vo, 2 60

Wolff's Windmill as a Prime Mover 8vo, 3 00

Woodbury's Fire Protection of Mills 8vo, 2 50

MATHEMATICS.

Baker's Elliptic Functions 8vo,

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Briggs's Elements of Plane Analytic Geometry 12mo,

Chapman's Elementary Course in Theory of Equation*. . .12m o,

Compton's Manual of Logarithmic Computations 12mo,

10

60
00
00
5i
50

Davis's Introduction to the Logic of Algebra 8vo, 1 10

•Dickson's College Algebra Large 12mo, 1 60

* " Introduction Jo the Theory of Algebraic Equations.

Large 12mo, 1 2£

Halsted's Elements of Geometry 8vo, 1 75

" Elementary Synthetic Geometry 8vo, 1 50

•Johnson's Three-place Logarithmic Tables: Vest-pocket size,

pap., 16

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" Elementary Treatise on the Integral Calculus.

Small 8vo, 1 50

" Curve Tracing in Cartesian Co-ordinates 12mo, 1 00

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Equations Small 8vo, 3 50

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* « Theoretical Mechanics ,..12mo, 3 Of

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Baldwin's Steam Heating for Buildings 12mo, 2 50

Bairns Kinematics of Machinery 8vo, 2 50

* Bartlett's Mechanical Drawing 8vo, 3 00

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Carpenter's Experimental Engineering 8vo, 6 00

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Durley's Kinematics of Machines 8vo, 4 00

Flather's Dynamometers, and the Measurement of Power . . 12mo, 3 00

Rope Driving 12mo, 2 00

Gill's Gas an Fuel Analysis for Engineers 12mo, 1 26

Hall's Car Lubrication 12mo, 1 00

Jones's Machine Design:

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Kent's Mechanical Engineers' Pocket-book 16mo, morocco, 5 00

Kerr's Power and Power Transmission 8vo, 2 00

11

MacCord's Kinematics; or, Practical Mechanism 8vo, 5 00

Mechanical Drawing 4to, 4 00

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Mahan's Industrial Drawing. (Thompson.) 8vo, 3 60

Pople's Calorific Power of Fuels 8vo, 3 00

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Richards's Compressed Air 12mo, 1 60

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Animal as a Machine and Prime Motor and the

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Hydraulics and Hydraulic Motors. (Du Bois.) .8vo, 5 00

Wolff's- Windmill as a Prime Mover 8vo, 3 00

Wood's Turbines 8vo, 2 60

MATERIALS OF ENGINEERING.

Bovey's Strength of Materials and Theory of Structures. .8vo, 7 60
Burr's Elasticity and Resistance of the Materials of Engineer-
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Church's Mechanics of Engineering 8vo, 6 00

Johnson's Materials of Construction Large 8vo, 6 00

Keep's Cast Iron 8vo, 2 60

Lanza's Applied Mechanics 8vo, 7 60

Martens's Handbook on Testing Materials. (Henning.) . . . .8vo, 7 60

Merriman'a Text-book on the Mechanics of Materials. .. .8vo, 4 00

Strength of Materials 12mo, 1 00

Metcalf's Steel. A Manual for Steel-users 12mo, 2 00

Smith's Wire: Its Use and Manufacture Small 4to, 3 00

" Materials of Machines 12mo, 1 00

Thurston's Materials of Engineering 3 vols., 8vo, 8 00

Part II.— Iron and Steel 8vo, 3 60

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Thurston's Text-book of the Materials of Construction 8vo, 6 00

Wood's Treatise on the Resistance of Materials and an Ap-
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" Elements of Analytical Mechanics 8vo, 3 00

STEAM ENGINES AND BOILERS.
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12mo, 1 60
Dawson's " Engineering " and Electric Traction Pocket-book.

16mo, morocco, 4 00

Ford's Boiler Making for Boiler Makers 18mo, 1 00

Goss's Locomotive Sparks ,8vo, 2 00

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Button's Mechanical Engineering of Power Plants 8vo, 6 00

" Heat and Heat-engines 8vo, 6 00

Kent's Steam-boiler Economy 8vo, 4 00

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MacCord'a Slide-valves 8vo, 2 00

Meyer's Modern Locomotive Construction 4to, 10 00

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" Tables of the Properties of Saturated Steam and

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Heat-engines 8vo, 6 00

" Valve-gears for Steam-engines. 8vo, 2 60

Peabody and Miller. Steam-boilers 8vo, 4 00

Fray's Twenty Years with the Indicator .Large 8vo, 2 60

Pupin's Thermodynamics of Reversible Cycles in Gases and

Saturated Vapors. (Osterberg.) 12mo, 1 26

Reagan's Locomotive Mechanism and Engineering 12mo, 2 50

Rontgen's Principles of Thermodynamics. (Du Bois.) . . . .8vo, 6 00

Sinclair's Locomotive Engine Running and Management. . 12mo, 2 00

Smart's Handbook of Engineering Laboratory Practice. . 12mo, 2 60

Snow's Steam-boiler Practice 8vo, 3 00

8pangler*s Valve-gears 8vo, 2 60

Notes on Thermodynamics 12mo, 1 00

Spangler, Greene, and Marshall's Elements of Steam-engineering.

8vo, 3 00

Thureton's Handy Tables 8vo, 1 60

" Manual of the Steam-engine 2 vols., 8vo, 10 00

Part I. — History, Structure, and Theory 8vo, 6 00

Part LI. — Design, Construction, and Operation 8vo, 6 00

Thurston's Handbook of Engine and Boiler Trials, and the Use

of the Indicator and the Prony Brake 8vo, 6 00

" Stationary Steam-engines 8vo, 2 60

Steam-boiler Explosions in Theory and in Prac-
tice 12mo, 1 60

" Manual of Steam-boilers, Their Designs, Construc-
tion, and Operation 8vo, 6 00

Weisbach's Heat, Steam, and Steam-engines. (Du Bois.)..8vo, 5 00

Whitham's Steam-engine Design 8vo, 6 00

Wilson's Treatise on Steam-boilers. (Flather.) 16mo, 2 60

Wood's Thermodynamics, Heat Motors, and Refrigerating

Machines 8vo, 4 00

MECHANICS AND MACHINERY.

Barr's Kinematics of Machinery 8vo, 2 60

Bovey's Strength of Materials and Theory of Structures. .8 vo, 7 60

Chorda!. — Extracts from Letters 12mo, 2 60

Church's Mechanics of Engineering 8vo, 6 00

Notes and Examples in Mechanics 8vo, 2 00

Compton's First Lessons in Metal- working 12mo, 1 60

Compton and De Groodt. The Speed Lathe 12mo, 1 60

Cromwell's Treatise on Toothed Gearing 12mo, 1 60

Treatise on Belts and Pulleys 12mo, 1 60

Dana's Text-book of Elementary Mechanics for the Use of

Colleges and Schools 12mo, 1 60

Dingey's Machinery Pattern Making 12mo, 2 09

Dredge's Record of the Transportation Exhibits Building of the

World's Columbian Exposition of 1893 4to, half mor., 6 00

Du Bois's Elementary Principles of Mechanics:

Vol. I.— Kinematics 8vo, S 50

Vol. H.— Statics 8vo, 4 00

Vol. HI.— Kinetics 8vo, 3 50

Du Bois's Mechanics of Engineering. Vol. I Small 4to, 7 60

Vol.H Small 4to, 10 00

13

Durley's Kinematics of Machines 8vo, 4 00

Fitzgerald's Boston Machinist 16mo, 1 00

Flather's Dynamometers, and the Measurement of Power. 12mo, 3 00

Rope Driving 12mo, 200

Goss's Locomotive Sparks 8vo, 2 00

Hall's Car Lubrication 12mo, 1 00

Holly's Art of Saw Filing 18mo, 75

* Johnson's Theoretical Mechanics 12mo, 8 00

Johnson's Short Course in Statics by Graphic and Algebraic

Methods. (In preparation.)
Jones's Machine Design:

Part I. — Kinematics of Machinery 8vo, 1 50

Part TI. — Form, Strength and Proportions of Parts. .. .8vo, 3 00

Kerr's Power and Power Transmission 8vo, 2 00

Lanza's Applied Mechanics 8vo, 7 60

MacCord's Kinematics; or, Practical Mechanism 8vo, 6 00

Velocity Diagrams 8vo, 1 50

Merriman's Text-book on the Mechanics of Materials 8vo, 4 00

* Michie's Elements of Analytical Mechanics 8vo, 4 00

Reagan's Locomotive Mechanism and Engineering 12 mo, 2 00

Reid's Course in Mechanical Drawing 8vo, 2 00

" Text-book of Mechanical Drawing and Elementary

Machine Design 8vo, 3 00

Richards's Compressed Air 12mo, 1 60

Robinson's Principles of Mechanism 8vo, 3 00

Ryan, Norris, and Hoxie's Electrical Machinery. (In preparation.)

Sinclair's Locomotive-engine Running and Management. . 12mo, 2 00

Smith's Press-working of Metals 8vo, S Of

" Materials of Machines 12mo, 1 00

Spangler, Greene, and Marshall's Elements of Steam-engineering.

8vo, 3 00

Thurston's Treatise on Friction and Lost Work in Machin-
ery and Mill Work 8vo, 3 00

Animal as a Machine and Prime Motor, and the

Laws of Energetics 12mo, 1 00

Warren's Elements of Machine Construction and Drawing. .8vo, 7 69
Weisbach's Kinematics and the Power of Transmission.

(Herrman— Klein.) 8vo, 5 00

Machinery of Transmission and Governors. (Herr-

(man— Klein.) 8vo, 5 00

Wood's Elements of Analytical Mechanics 8vo, 3 00

" Principles of Elementary Mechanics 12mo, 1 25

" Turbines 8vo, 850

The World's Columbian Exposition of 1893 4to, 1 Of

METALLUBGY.
Egleston's Metallurgy of Silver, Gold, and Mercury:

Vol. L-Silver 8vo, T to

Vol. IT.— Gold and Mercury 8vo, T §0

** Des's Lead-smelting (Postage 9 cents additional) 12mo, 2 50

Keep's Cast Iron 8vo, 2 50

Kunhardt's Practice of Ore Dressing in Llirope 8vo, 1 50

Le Ch atelier's High-temperature Measurements. (Boudouard —

Burgess.) 12mo, 3 00

Metcalf's Steel. A Manual for Steel-users 12mo, 2 00

Smith's Materials of Machines 12mo, 1 00

Thurston's Materials of Engineering. In Three Parts 8vo, 8 00

Part II.— Iron and Steel SYO, 3 50

Part III.— A Treatise on Brasses, Bronzes and Other Alloys

and Their Constituents 8vo, S M

14

MINERALOGY.

Barringer'i Description of Minerals of Commercial Value.

Oblong, morocco, 15 59

Boyd's Resources of Southwest Virginia 8vo, 300

" Map of Southwest Virginia Pocket-book form, 2 00

Brush's Manual of Determinative Mineralogy. (Penfield.) .8vo, 4 00

Cheater's Catalogue of Minerals 8vo, paper, 1 00

Cloth, 1 26

" Dictionary of the Names of Minerals 8vo, 3 60

Dana's System of Mjieralogy Large 8vo, half leather, 12 60

" First Appendix to Dana's New " System of Mineralogy."

Large 8vo, 1 00

" Text-book of Mineralogy 8vo, 4 00

* Minerals and How to Study Them 12mo, 1 60

* Catalogue of American Localities of Minerals. Large 8vo, 1 00

* Manual of Mineralogy and Petrography 12mo, 2 00

Bgleston's Catalogue of Minerals and Synonyms 8vo, 2 60

Husaak's The Determination of Rock-forming Minerals,

(Smith.) Small 8vo, 2 00

* Penfleld's Notes on Determinative Mineralogy and Record of

Mineral Tests 8vo, paper, 60

RosenbuBch's Microscopical Physiography of the Rock-making

Minerals. (Idding's.) 8vo, 8 00

•Tillman's Text-book of Important Minerals and Rocks.. 8vo, 2 00

Williams's Manual of Lithology 8vo, I 00

MINING.

B«ard'« Ventilation of Mines 12mo, 2 60

Boyd's Resources of Southwest Virginia 8vo, 3 Of

" Map of Southwest Virginia Pocket-book form, 2 00

•Drinker's Tunneling, Explosive Compounds, and Rock

Drills 4to, half morocco, 26 00

Eider's Modern High Explosives 8vo, 4 00

Fowler's Sewage Works Analyses 12mo, 2 00

Goodyear's Coal-mines of the Western Coast of the United

States 12mo, 260

Ihlseng's Manual of Mining 8vo, 4 00

** Des's Lead-smelting 12mo, 2 50

Kunhardt's Practice of Ore Dressing in Europe 8vo, 1 60

ODriscoll's Notes on the Treatment of Gold Ores 8vo, 2 00

Sawyer's Accidents in Mines 8vo, 7 00

* Walke's Lectures on Explosives 8vo, 4 00

Wilson's Cyanide Processes 12mo, 1 60

Wilson's Chlorination PTOCCM 12mo, 1 6t

Wlkon's Hydraulic and Placer Mining 12mo, £ 00

Wilson's Treatise on Practical and Theoretical Mine Ventila-
tion 12mo, 1 26

SANITAEY SCIENCE.

FolwelTa Sewerage. (Designing, Construction and Maintenance.)

8vo, 8 00

Water-supply Engineering 8vo, 4 00

Water and Public Health 12mo, 1 60

Water-nitration Works 12mo, 260

15

Gerhard's Guide to Sanitary House-inspection 16mo, 1 00

Goodrich's Economical Disposal of Towns' Refuse. . .Demy 8vo, S 10

Hazen's Filtration of Public Water-supplies 8vo, 8 00

Kiersted's Sewage Disposal 12mo, 1 25

Leach's The Inspection and Analysis of Food with Special

Reference to State Control. (In preparation.)
Mason's Water-supply. (Considered Principally from a San-
itary Standpoint. 3d Edition, Rewritten 8vo, 4 00

" Examination of Water. (Chemical and Bacterio-
logical.) 12mo, 1 25

Merriman's Elements of Sanitary Engineering 8vo, 2 00

Nichols's Water-supply. (Considered Mainly from a Chemical

and Sanitary Standpoint.) (1883.) 8vo, 2 60

Ogden's Sewer Design 12mo, 2 00

* Price's Handbook on Sanitation 12mo, 1 60

Richards's Cost of Food. A Study in Dietaries 12mo, 1 Of

Richards and Woodman's Air, Water, and Food from a Sani-
tary Standpoint 8vo, 2 00

Richards's Cost of Living as Modified by Sanitary Science . 12mo, 1 00

* Richards and Williams's The Dietary Computer 8vo, 1 60

Rideal's Sewage and Bacterial Purification of Sewage 8vo, 8 60

Turneaure and Russell's Public Water-supplies 8vo, 6 00

Whipple's Microscopy of Drinking-water 8vo,* 3 60

Woodhull's Notes on Military Hygiene 16mo, 1 60

MISCELLANEOUS.

Barker's Deep-sea Soundings 8vo, 2 00

Emmous's Geological Guide-book of the Rocky Mountain Ex-
cursion of the International Congress of Geologists.

Large 8 vo, 1 60

FerreFs Popular Treatise on the Winds 8vo, 4 00

Raines's American Railway Management 12mo, 2 60

Mott's Composition, Digestibility, and Nutritive Value of Food.

Mounted chart, 1 26

" Fallacy of the Present Theory of Sound 16mo, 1 00

Ricketts's History of Rensselaer Polytechnic Institute, 1824-

1894 Small 8vo, 3 00

Rotherham's Emphasised New Testament Large 8vo, S 00

Steel's Treatise on the Diseases of the Dog 8vo, 3 60

Totten's Important Question in Metrology 8vo, 2 60

The World's Columbian Exposition of 1893 4to, 1 00

Worcester and Atkinson. Small Hospitals, Establishment and
Maintenance, and Suggestions for Hospital Architecture,

with Plans for a Small Hospital 12mo, 1 86

HEBREW AND CHALDEE TEXT-BOOKS.

Green's Grammar of the Hebrew Language 8vo, 8 00

" Elementary Hebrew Grammar 12mo, 1 26

" Hebrew Chrestomathy 8vo, 2 00

Ctoeenius's Hebrew and Chaldee Lexicon to the Old Testament

Scriptures. (Tregelles.) Small 4to, nail morocco, 6 W

Letteris's Hebrew Bible 8vo, 2 26

16

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«*BOOK?DUEW

=fi^MPED BELOW

NOV24K^f

clAN - 5 1959

SEP 25 1S19

ArSj

YC 18786